A78 Hunterston Roundabout to Highthorne: Survey, Hazards, Risks, Mitigations
March 2013
To be read in conjunction with A78 Pictorial Survey, Hunterston Roundabout to Highthorne
This work starts at the south side of the Hunterston Roundabout; the roundabout itself is not included (the detail of the Ordnance Survey map shows an accident cluster in the vicinity of the
roundabout).
Unless otherwise stated, distances are measured to or from the near edge of a junction.
Interval Characterisation
The A78 (T) is the main north-south route for North Ayrshire. It is a busy road, but seldom sees significant queuing / congestion. Usage includes private vehicles and all sizes of commercial
vehicles. This 2.25km interval of the A78 runs through an agricultural area, and comprises 2 distinct sections. It is a single lane carriageway; the national speed limit applies (60mph for cars down
to 40mph for heavy trucks).
The northern 1km from the Hunterston Roundabout to just south of the Kilruskin junction was realigned in conjunction with Hunterston developments; this included establishing fairly wide road-side
verges (but not footways) – usually 2–3m wide. Because the curvature is gentle and uniform, it is possible to drive along at speed; however, it is not well suited for overtaking at higher speeds, as
the curvature limits forward vision. The carriageway width is around 7.0m.
The 1.25km interval to the south is dead straight, and narrower – around 6.56m at the lay-by. The verges are generally narrower, and bordered by hedges / fencing. Some drivers entering this
straight stretch see it as an opportunity to overtake; equally, north bound drivers see an overtaking opportunity starting at the B782 junction (at Highthorne).
There is a cluster of serious accidents just south of the Kilruskin Road T-junction, where the curved road interval transitions into the straight section; the length of the cluster section is about 220
metres. There is a second cluster of serious accidents at the B782 Highthorne junction. The A78 has a partial blind characteristic at each of these cluster sites.
Hazards and Risks
These are ranked according to the rationale set out in Support Package SP C3
Accident History
Refer to the Summary Maps, which show individual injury accidents over the last 23 years. The accidents are categorised according to the severity of injuries suffered – slight, serious or fatal.
Accident cluster sites are obvious from this map, and there is a clear correlation between these and identified Hazard Areas.
++
Survey and Hazard Identification
This is split into 4 parts:
1.
2.
3.
4.
A78 to north of the Kilruskin Junction
Kilruskin T-Junction
A78 between Kilruskin Junction and the turning into Hunterston Estate
The trio of junctions at Highthorne
Part 1: A78 to north of the Kilruskin Junction
This interval of carriageway is described above under Interval Characterisation. The only apparent hazard is the interface between motor vehicles and cyclists - who do not have a separate Cycle
Way (there is no cyclist warning sign). See photos 1 – 5.
Part 2: A78 / Kilruskin Road T-Junction Refer to photos 4, 5 and 6
Carried out November 2011 and December 2012
There is a cluster of serious accidents just south of the Kilruskin Road T-junction, where the curved road interval transitions into the straight section; the length of the cluster section is about 400
metres.
Road type
Traffic Flows
A78(T) to south of
junction (Ardrossan side)
A78(T) to north of junction (Largs side)
Single-lane rural A-road,
no central reservation
Single-lane rural A road, no central
reservation; was realigned in conjunction
with Hunterston developments, including
establishing broad side verges (no
footways)
Steady; broadly equal flows in both directions; most traffic leaving the
A78 to join the Kilruskin Road is turning left, having come from the Largs
side.
“Rush-hour” traffic (including Hunterston shift changes) adds significantly
to traffic flows.
Condition of
carriageway
surface
Current Speed
Limits
Speed
Considerations
Kilruskin Road to east of junction
Single lane unclassified rural road; width at
junction before the bell-mouth is about 20 feet
(6m)
Hazard Area 1: Kilruskin Rd / A78 Tjunction
Refer to photos 4, 5 & 6
Contributing Factors
Lighter, broadly equal flows in both directions.
More traffic turns right (north towards Hunterston
/ Largs) than left.
Most traffic entering Kilruskin Road at the
junction is turning left (having come from the
Hunterston / Largs side)
The application of the national speed limit
(60mph for cars)
Joining the A78 from Kilruskin Road:
+ the line of sight to the left (south) only
opens up when about 5m from the junction
edge
+ the junction is Give Way rather than
Stop
Generally sound
Generally sound
+ traffic joining the A78 has to negotiate 1
or 2 fast-moving traffic flows
National Speed Limit (60 mph for cars, down to 40mph for heavy trucks)
The carriageway contours on the junction approaches mean that 60 mph
is not a difficult speed to maintain.
+ driver may intend turning without first
stopping at the junction
Gauging the speed of approaching traffic from
the south is more difficult (traffic is coming
almost straight-on to the waiting car due to the
slight carriageway curvature).
Gauging the speed of approaching traffic from
the north is a little easier due to the approach
angle.
+ There is no restriction on overtaking on
the A78
+ The A78 here sees significant numbers
of recreational cyclists
Turning right from A78 into Kilruskin
Road
Road contours
approaching
junction
A78(T) to south of
junction (Ardrossan side)
A78(T) to north of junction (Largs side)
A gentle uniform left curve;
generally level
A gentle uniform right curve; generally
level
Kilruskin Road to east of junction
Almost straight (slight curvature to right);
downhill
+ Driver must cross fast-moving A78
south-bound traffic
+ Driver has no right-turn filter lane
Margin for Error: Low
Hazard Area 1 Ranking: Level 5,
Significant
Photo 5: 4.8m from junction edge, looking
south along A78; line of sight opening up
The junction is divided by an island to separate
the 2 traffic flows. The island carries 2 Keep Left
signs.
Arrangement of
Junction
There is a wide bell-mouth.
Lines of sight
The junction is visible when approaching it. It has a reflector post on
each side of the bell-mouth.
The line of sight along both directions of the A78
is not good till about 12 yards from the junction
at which point the line of sight is established to
the right (north); the line of sight to the left
(south) only opens up about 4.8 yards from the
junction edge.
The carriageway has a central hazard warning line, starting about 112
yards from the near edge of the junction, on the south and north
approaches.
There is a central hazard warning line up to the
junction.
There is an edge line at both edges of the carriageway.
There is a give way sign about 20 yards before
the junction, and a give way triangle is painted
on the carriageway just before the junction.
Roadside
Vegetation
Carriageway
Markings and
Signs
approaching the
junction
There are reflectors along both edges of the carriageway and along the
centre of the carriageway.
There are no prohibitions on overtaking on the A78 to north and south of
At the junction, there are double broken lines
across the left carriageway (give way at major
A78(T) to south of
junction (Ardrossan side)
A78(T) to north of junction (Largs side)
the junction
There is a reflector post in the verge on each side of the bell-mouth.
Kilruskin Road to east of junction
carriageway), and a single broken line across
the right carriageway.
There are no town directional signs at the
junction.
There is a Direction sign to West Kilbride located about 112 yards short
of the junction to the north and south.
Carriageway
Lighting
none
none
Part 3: Mainly straight interval of Carriageway from south of Kilruskin T-junction along to right turn into Hunterston Estate Road – Refer to photos 7 - 12
As stated under Interval Characterisation: This 1.25 km interval to the south is dead straight, and narrower - 6.56m measured at the lay-by. The verges are generally narrower, and bordered by
hedges / fencing. Some drivers entering this straight stretch see it as an opportunity to overtake; equally, north bound drivers see an overtaking opportunity starting at the B782 junction at
HIghthorne.
There is a cluster of serious accidents at the north end, just south of the Kilruskin Road T-junction, where the curved road interval transitions into the straight section; the length of the cluster section
is about 400 metres. At this transition there is a partially blind characteristic.
Hazard Area 2: Partially blind transition and straight interval of A78 from just south of Kilruskin T-junction along to right turn onto Hunterston Estate Road.
See Photos 7 – 10 & 13
Contributing Factors
Singly and in combination:
+ For a driver heading south, there is a blind interval of road in the transition between the curved and straight sections, more pronounced to the driver’s right side of road
+ Encountering an overtaking driver – maybe impatient - and who makes a misjudgement
+ The relative narrowness of the carriageway
+ The national speed limit of 60mph for cars
+ The low margin for error associated with speed and narrow carriageways
+ The zero margin for error associated with vehicles passing in the presence of a cyclist
+ The introduction of a sudden need to brake, coming from traffic appearing from the Kilruskin junction, the Hunterston estate junction, the B782 junction, or over the blind brow at Highthorne – or
from the lay-by
+ The compounding of these scenarios when a traffic flow in one direction meets a similar scenario approaching from the opposite direction.
Margin for Error: Low, sometimes none
Hazard Area 2 Ranking: Level 7, Serious
++
Part 4: Survey of Trio of A78 T-Junctions at Hunterston Estate Road, Highthorne Road (B782), and Thirdpart Road
Refer to photos 12 – 27
There is a cluster of serious accidents at the B782 Highthorne and Thirdpart junctions; the road interval is about 220 metres
A78 at south side of B782 junction (from Ardrossan)
Road Type
A78 at north side of B782
junction (from Largs)
Single-lane rural A-carriageway (no central reservation)
The interval of A78 around the B782 junction is around 6.50m wide, and is straight.
There is a blind bend at its southern end (just north of Carlung Farm) and a blind brow
and down-slope just north of the junction; the blind brow is not sign-posted
Some north-bound drivers entering this straight stretch see it as an opportunity to
overtake, starting at the B782 junction at Highthorne.
B782 to east of junction (from West
Kilbride)
Single-lane rural B-carriageway; width
at junction is about 6.9m. The
carriageway has no markings from
West Kilbride till just before the
junction. It is characterised by farm
accesses (6); field accesses (many);
bends, hills; roadside vegetation which
includes hedges. The above
contribute to limited lines of sight along
its length.
Junctions
Hazard Area, Contributing
Factors, Margin for Error,
Hazard Area Ranking
Please refer to photo survey
and detail from OS Map.
Hazard Area 3: Hunterston
Estate Road Junction and
adjacent interval of A78
Refer to photos 10 - 13
Contributing Factors
Singly and in combination
The three T-junctions are spaced as follows along a 400 yard interval of the A78:


At 257 yards north of the B782 junction is the T-junction on the west to Hunterston Estate
At about 134 yards south of the B782 junction is the T-junction on the west to Thirdpart
The A78 signage for these 3 junctions is as follows:
Hunterston
260 yards from B782
West Kilbride
(B782)
Coming from North
no
yes
Coming from South
no
yes
Thirdpart
134 yards from B782
yes (added 2012)
yes
+ traffic joining the A78 has to
negotiate 1 or 2 fast-moving
traffic flows
+ the junction’s proximity to the
B782 junction, at which point
overtaking is permitted for
north-bound A78 traffic; the
blind brow contributes to this
hazard
+ its position in the A78 southbound overtaking zone
+ the junction is not sign-
posted on the A78
+ there is no right turn filter
lane for traffic leaving the A78
at the junction (the carriageway
is to narrow to have one)
+ the absence of clear
markings and signage at the
junction
+ the narrowness of the A78
carriageway reduces margins
for error
+ a footway / cycleway crosses
the Hunterston Estate Road
just short of the A78, obliging
drivers turning off the A78 to
yield to cyclists / pedestrians
+ on top of the foregoing is the
application of the national
speed limit – 60 mph for cars
Margin for Error : Very Low
Hazard Area 3 Ranking: Level
7, Serious
Traffic Flows
A78 flows are steady, broadly equal flows in both directions. Rush-hour traffic (including
from Hunterston power stations) adds significantly to traffic flows.
Of the 3 junctions, the busiest is the B782; the least used is the Hunterston Estate Road.
Lighter, broadly equal flows in both
directions; more traffic turns right
(north towards Largs) than left.
Most traffic entering the B782 at the
junction is turning left (having come
from the Hunterston / Largs side).
Hazard Area 4: B782 Tjunction and adjacent intervals
of A78
Refer to photos: 12 – 17 & 24
Contributing Factors
Accidents
Singly and in combination
For the interval of the A78 between Carlung and about 400 yards to the north of the B782
junction, the accident record is bad: there have been several deaths and serious injuries.
+ traffic joining the A78 has to
negotiate 1 or 2 fast-moving
traffic flows
There is a cluster of serious accidents at the B782 Highthorne and Thirdpart junctions
Speed Limits
National speed limit, 60 mph for cars, 40mph for heavy trucks
National speed limit
+ the partially blind brow at the
north side of the junction results
in limited lines of sight along the
Speed
Considerations
The carriageway contours and straightness of this stretch of the A78 mean that 60 mph is
not a difficult speed to maintain.
It is common to see traffic flows travelling at 40 mph; but it is also common to see
occasional drivers at 60 mph, and overtaking.
Carriageway
contours
approaching junction
Level carriageway up to the junction, then dips
downhill; carriageway is straight
Uphill slope towards the junction;
carriageway is straight
Gauging the speed of approaching
A78 traffic is not easy; to the north it is
made more difficult due to the blind
brow at the start of the down-slope.
Level carriageway, final approach is at
right angles to the A78. The bellmouth at the junction allows for
vehicles to turn smoothly.
A78 to the north when joining
from the B782 – until almost at
the junction edge
+ Correspondingly, the junction
is partly obscured from about
160 yards to the north; and the
junction’s visibility on the
approach is not prominent
+ the partially blind brow at the
north side of the junction results
in A78 traffic approaching from
the north being blind to traffic
approaching the junction from
the south – and vice-versa
+ the status of the junction as
Give Way instead of Stop
+ the overtaking restriction for
north-bound traffic is lifted at the
junction
+ there are no turning filter
lanes for traffic leaving the A78
at the junction (the carriageway
is not wide enough for these,
although the land is there)
+ the width of the A78
carriageway reduces margins
for error
+ the presence of cyclists,
pedestrians and equestrian
users
+ on top of the foregoing is the
application of the national
speed limit – 60 mph for cars
Margin for Error: Very Low
Hazard Area 4 Ranking: Level
8, Very Serious
Lines of Sight
A car approaching the B782 junction from the
south will find the line of sight along the A78 to
the north is impaired immediately north of the
junction due to the brow of the hill
A car approaching the junction from
the north will find the line of sight
along the A78 to the south of the
junction impaired due to the brow of
A car at the junction about to join the
A78 has clear line of sight to the left
(south) when about 10 yards from the
junction.
Hazard Area 5: Thirdpart Tjunction and adjacent intervals
the hill
Roadside Vegetation
Carriageway
Markings and road
signs approaching
the junction
Not obscuring the junction
The carriageway is marked as follows, from
south to north; distances are to the near edge of
the B782 junction:
+ solid double white lines up to the junction; at
the junction this changes to broken / solid lines,
(overtaking permitted heading north)
+ edge lines at both edges of the carriageway
up to and beyond the junction
reflectors along both edges of the
carriageway and down the centre of the
carriageway
+
+ Greenock / Hunterston / West Kilbride
direction sign 114 yards before the junction
+ Greenock / Hunterston / West Kilbride
direction sign at the junction
To the right (north) he has clear line of
sight only once he is about 1 yard
from the junction; however, once he
has this line of sight, the down-slope
curvature of the carriageway will cut
off the lower part of approaching
vehicles at a distance of about 160
yards.
If grass is allowed to grow in the area
on the north-east side of the junction,
the reduction in the line of sight
mentioned above is aggravated.
The carriageway is marked as
follows, from north to south; distances
are to the near edge of the B782
junction:
+ edge line at both edges of the
carriageway up to and beyond the
junction.
+ reflectors along both edges of the
carriageway and down the middle of
the carriageway.
+ At 345 yards from junction there is
a cyclist route warning sign.
+ At 235 and 205 yards, Get-In-toLeft arrows painted on the
carriageway
+ At 166 yards, an Irvine / West
Kilbride direction sign.
+ At 175 yards, the carriageway
centre line changes to solid / broken
white lines which continue to the
junction (no overtaking heading
south); at the B782 junction they
change to double solid lines which
run up to the far side of the dogleg
bend.
+ A left T-junction-ahead sign at 120
yards
+ A white square painted in the
middle of each carriageway at 88
of A78
Refer to photos:18 - 27
Contributing Factors
Singly and in combination
+ the absence of clear
markings and signage for the
junction
+ traffic joining the A78 has to
negotiate 1 or 2 fast-moving
traffic flows
+ There are no line markings on this
carriageway from West Kilbride until
about 42 yards before the junction;
from this point up to the junction, the
centre of the carriageway is marked
with a hazard warning line.
+ traffic joining the A78 has
very restricted line of sight
along the A78 to the south –
which opens up only when car
is 2 yards from carriageway
edge
+ cyclist route warning sign 100 yards
from the junction.
+ the status of the junction as
Give Way (?) instead of Stop
+ 8 yards before the junction there is
a Give Way sign, and a white Give
Way warning triangle painted on the
carriageway.
+ its proximity to the dogleg
bend to the south – 175 yards,
which equates to the 55 mph
wet-road stopping distance; and
to the B782 T-junction to the
north
+ At the junction, there are double
broken lines across the left
carriageway (give way at major
carriageway) and a single broken line
across the right carriageway.
+ There are Irvine & Greenock
direction signs on the far side of the
junction.
+ the narrowness of the A78
carriageway reduces margins
for error
+ there is no right turn filter
lane for traffic leaving the A78
at the junction (the carriageway
is not wide enough for this)
+ the presence of cyclists,
pedestrians and equestrian
users; the junction has an
A78(T) pavement to left and
right.
+ the presence of slower
moving agricultural traffic and
‘horse-box’ traffic
+ the slow tight turn for traffic
yards
turning left off the A78
+ The word SLOW is painted on the
carriageway at about 72 yards
+ the bell-mouth at the junction
allows for vehicles to turn
smoothly, but the narrowness of
the Thirdpart road does not
allow for 2 vehicles to pass in
the immediate vicinity of the
junction. Consequently longer
vehicles entering the Thirdpart
road are required to wait on the
A78 to allow an exiting vehicle
to clear the junction.
+ A left bend sign at 34 yards, which
refers to the dogleg bend beyond the
Thirdpart T-junction
+ on top of the foregoing is the
application of the national
speed limit – 60 mph for cars
Margin for Error: Very Low
Hazard Area 5 Ranking: Level
8, Very Serious
Traffic Calming
features
Nothing other than stated above
no
Road Lighting
no
Footways
Yes, on the west side and separated from the carriageway by a 3m (varies) wide grass
verge (this footway runs from Seamill to about 400 yards north of the junction).
no
Provision for Cyclists
and Pedestrians
+ Cyclist Route Ahead warning sign about 50
yards before left turning to Thirdpart
+ Cyclist Route Ahead warning sign
about 100 yards from the junction.
no
+ Cyclist Route Ahead warning sign
about 345 yards from the junction.
no
+ A Cyclist and Pedestrian use sign marks the
continuation of the footpath on the north side of
the Thirdpart T-junction.
+ Sign indicating off-carriageway
cycle path about 35 yards from the
junction.
+ A Cyclist and Pedestrian direction sign is
located on the pavement at the junction
+ There is a short cycle-way
separated from the carriageway for
last few yards of the approach to the
junction. A Cyclists Dismount sign is
located on this path just short of the
A78.
Bus Stops
Provision for Horse
Riders
Unmarked bus stops are in use about
30 yards from the A78
Recreational horse riding is popular in this area. Horses are stabled at Thirdpart, and nearby at Millstonford immediately to the
north-east of the junction. Riders typically cross the B782 about 30 yards from the A78 junction, then pass along the cycle way and
cross the A78 to the footway which then gives access to the rural (unclassified) road to Thirdpart.
Risk Assessment
Possible Outcomes
Hazard Area, Contributing Factors, Margin for Error,
Hazard Area Ranking
Possible Events
Relative Likelihood
Hazard Area
Risk Level
Manageability
In General
Principal road features which lead to hazards and risks
include the following:
+ A single-lane A-road which is relatively narrow in parts,
with a national speed limit which is seen as too high when
gauged against current Government guidelines
+ The close proximity of 3 T-junctions to one another,
which do not all have good lines of sight - coupled to a
nearby blind dogleg bend and a blind brow. Traffic joining
the A78 must negotiate 1 or both lanes of fast-moving traffic.
+ A short straight interval of the A78 bounded on both
sides by intervals not well suited for overtaking; on this
interval, the narrow carriageway cannot accommodate 3
adjacent vehicles: this has a major impact on margin for
driver error when overtaking.
In general, the risk of an accident comes from the road
system’s characteristics, in conjunction with driver behaviours,
including speed, inattention, error of judgement
Possible events include the following, or variations on these:
+ Vehicles colliding associated with overtaking
+ Vehicles colliding associated with joining the A78 at rural T
junctions
+ Vehicles impacting from behind
+ Vehicles running off road
+ The presence of other road users
Possible Outcomes
Varies – see notes below on each
individual Hazard Area
Varies – see
each individual
Hazard Area in
tabulation
Hazard
Managment and
Mitigations
+ The status of these 3 T-junction as Give Way instead of
Stop, and the absence of further constraints on speed
+ The presence of other road users – pedestrian, cyclist,
equestrian – albeit in small numbers
Hazard Area 1: Kilruskin Rd / A78 T-junction
Refer to photos 4, 5 & 6
Contributing Factors
The application of the national speed limit (60mph for cars)
Joining the A78 from Kilruskin Road:
+ the line of sight to the left (south) only opens up when
about 5m from the junction edge
+ the junction is Give Way rather than Stop
+ traffic joining the A78 has to negotiate 1 or 2 fast-moving
+ Driver on Kilruskin Road approaches junction intending not
to stop unless necessary, and in the seconds available to
make his decision, he misjudges the presence and speed of
A78 traffic, leading to a collision
Possible Outcomes
+ Driver stops at junction, but still misjudges nature and
speed of approaching traffic, presence of other road users,
leading to a collision
Vehicle runs off the road, through
fence
+ driver misses his gear change / stalls when starting his turn
Near miss, Injury , Death
Collision with other vehicle (possible
but less likely with a cyclist)
resulting in
+ Confusion sets in between drivers turning right, one joining
and one leaving the A78
Relative Likelihood
Hazard Area 1
Risk: Level 5,
Significant
Possible Outcomes
Hazard Area, Contributing Factors, Margin for Error,
Hazard Area Ranking
Possible Events
Relative Likelihood
Hazard Area
Risk Level
Manageability
traffic flows
For the possible events shown, the
relative likelihood is categorised as
Medium
+ driver may intend turning without first stopping at the
junction
+ There is no restriction on overtaking on the A78
+ The A78 here sees significant numbers of recreational
cyclists
The A78 immediately to the south of
the junction is the sight of a cluster
of serious accidents
Turning right from A78 into Kilruskin Road
+ Driver must cross fast-moving A78 south-bound traffic
+ Driver has no right-turn filter lane
Margin for Error: Low
Hazard Area 1 Ranking: Level 5, Significant
Hazard Area 2: Partially blind transition and straight interval
of A78 from just south of Kilruskin T-junction along to just
north of right turn onto Hunterston Estate Road.
+ A range of accident associated with speed on a rural singlelane trunk road with narrow lanes. These could be shunts,
head-on collisions, running off the road.
Possible Outcomes
See Photos 7 – 10, & 13
+ As well as involving other vehicles, they could involve
cyclists and motor cyclists.
Collision with other vehicle (possible
but less likely with a cyclist)
+ The presence at the southerly end of the branch road to
Hunterston Estate and the rise and partially blind brow at
Highthorne compound matters.
Vehicle runs off the road, through
fence
Contributing Factors
Singly and in combination:
+ For a driver heading south, there is a blind interval of road
in the transition between the curved and straight sections,
more pronounced to the driver’s right side of road
+ Encountering an overtaking driver – maybe impatient and who makes a misjudgement
+ The relative narrowness of the carriageway
+ The national speed limit of 60mph for cars
+ The low margin for error associated with speed and
narrow carriageways
+ The zero margin for error associated with vehicles
passing in the presence of a cyclist
resulting in
Near miss, Injury , Death
Relative Likelihood
For the possible events shown, the
relative likelihood is categorised as
Higher than Medium
Hazard Area 2
Risk: Level 7,
Serious
Possible Outcomes
Hazard Area, Contributing Factors, Margin for Error,
Hazard Area Ranking
Possible Events
Relative Likelihood
Hazard Area
Risk Level
Manageability
+ The introduction of a sudden need to brake, coming from
traffic appearing from the Kilruskin junction, the Hunterston
estate junction, the B782 junction, or over the blind brow at
Highthorne – or from the lay-by
+ The compounding of these scenarios when a traffic flow
in one direction meets a similar scenario approaching from
the opposite direction.
Margin for Error: Low, sometimes none at all
Hazard Area 2 Ranking: Level 7, Serious
Hazard Area 3: Hunterston Estate Road Junction and
adjacent interval of A78
Refer to photos 10 - 13
Contributing Factors
Singly and in combination
+ traffic joining the A78 has to negotiate 1 or 2 fast-moving
traffic flows
The possible events are similar to those stated above for
Hazard Area 4 below:
A range of accidents associated with a T-junction of a 60mph
A-road (with no central reservation) and a rural B-road. The
right turn – across 1 or both fast-moving flows is notorious; the
left turn is also dangerous. The possibility of an overtaking
vehicle approaching downhill from the B782 junction
compounds what could happen.
Possible Outcomes
Collision with other vehicle (possible
but less likely with a cyclist or
pedestrian)
Vehicle runs off the road, through
fence
+ the junction’s proximity to the B782 junction, at which
point overtaking is permitted for north-bound A78 traffic; the
blind brow contributes to this hazard
Joining the A78
resulting in
Driver misjudges the speed of the 2 approaching traffic flows,
and proceeds when unsafe to do so
Near miss, Injury , Death
+ its position in the A78 south-bound overtaking zone
Leaving the A78
+ the junction is not sign-posted on the A78
Driver misjudges speed of Approaching A78 traffic
+ there is no right turn filter lane for traffic leaving the A78
at the junction (the carriageway is to narrow to have one)
Driver obliged to stop on A78 and wait for pedestrian or
cyclists to clear the junction
+ the absence of clear markings and signage at the
junction
Right-turning driver does not notice an overtaking vehicle from
behind.
+ the narrowness of the A78 carriageway reduces margins
for error
Carrying on along A78
+ a footway / cycleway crosses the Hunterston Estate
Road just short of the A78, obliging drivers turning off the
A78 to yield to cyclists / pedestrians
+ on top of the foregoing is the application of the national
Overtaking vehicle south-bound runs out of forward vision as
he approaches the blind brow; or meets no overtaking
restriction before he can complete the manoeuvre.
Relative Likelihood
For the possible events shown, the
relative likelihood is categorised as
Higher than Medium
Hazaard Area 3
Risk: Level 7-,
Serious
(the 7- refers to
the relatively low
usage of the
Hunterston
Estate Road)
Possible Outcomes
Hazard Area, Contributing Factors, Margin for Error,
Hazard Area Ranking
Possible Events
Relative Likelihood
Hazard Area
Risk Level
Manageability
speed limit – 60 mph for cars
Margin for Error : Very Low
Hazard Area 3 Ranking: Level 7, Serious
Hazard Area 4: B782 T-junction and adjacent intervals of
A78
Refer to photos: 12 – 17 & 24
Contributing Factors
Singly and in combination
+ traffic joining the A78 has to negotiate 1 or 2 fast-moving
traffic flows
+ the partially blind brow at the north side of the junction
results in limited lines of sight along the A78 to the north
when joining from the B782 – until almost at the junction
edge
+ Correspondingly, the junction is partly obscured from
about 160 yards to the north; and the junction’s visibility on
the approach is not prominent
+ the partially blind brow at the north side of the junction
results in A78 traffic approaching from the north being blind
to traffic approaching the junction from the south – and
vice-versa
+ the status of the junction as Give Way instead of Stop
+ the overtaking restriction for north-bound traffic is lifted
at the junction
+ there are no turning filter lanes for traffic leaving the A78
at the junction (the carriageway is not wide enough for
these, although the land is there)
+ the width of the A78 carriageway reduces margins for
error
+ the presence of cyclists, pedestrians and equestrian
users
A range of accidents associated with a T-junction of a 60mph
A-road (with no central reservation) and a rural B-road. The
right turn – across 1 or both fast-moving flows is notorious; the
left turn is also dangerous.
Joining the A78
Driver misjudges the speed of the 2 approaching traffic flows,
and proceeds when unsafe to do so
Possible Outcomes
Collision with other vehicle (possible
but less likely with a cyclist or
pedestrian)
Vehicle runs off the road, through
fence
Driver tries to turn without first stopping, leading to error of
judgement; may miss his gear change / stalls
resulting in
Leaving the A78
Near miss, Injury , Death
Driver misjudges speed of approaching A78 traffic
Driver obliged to stop on A78 and wait for pedestrian or
cyclists to clear the junction
Right-turning driver does not notice an overtaking vehicle from
behind.
Carrying on along A78
Overtaking vehicle south-bound runs out of forward vision as
he approaches the blind brow; or meets no overtaking
restriction before he can complete the manoeuvre.
Generally
Driver unfamiliar with the hazards in this area may be caught
out by behaviours of familiar drivers
Relative Likelihood
For the possible events shown, the
relative likelihood is categorised as
Higher
Hazard Area 4
Risk: Level 8,
Very serious
Possible Outcomes
Hazard Area, Contributing Factors, Margin for Error,
Hazard Area Ranking
Possible Events
Relative Likelihood
Hazard Area
Risk Level
Manageability
+ on top of the foregoing is the application of the national
speed limit – 60 mph for cars
Margin for Error: Very Low
Hazard Area 4 Ranking: Level 8, Very Serious
Hazard Area 4 Risk: Level 8, Very Serious
Hazard Area 5: Thirdpart T-junction and adjacent intervals
of A78
Refer to photos:18 - 27
Contributing Factors
Singly and in combination
+ the absence of clear markings and signage for the
junction
+ traffic joining the A78 has to negotiate 1 or 2 fast-moving
traffic flows
+ traffic joining the A78 has very restricted line of sight
along the A78 to the south –which opens up only when car
is 2 yards from carriageway edge
+ the status of the junction as Give Way (?) instead of
Stop
+ its proximity to the dogleg bend to the south – 175 yards,
which equates to the 55 mph wet-road stopping distance;
and to the B782 T-junction to the north
The possible events are similar to those stated above for
Hazard Area 4:
A range of accidents associated with a T-junction of a 60mph
A-road (with no central reservation) and a rural B-road. The
right turn – across 1 or both fast-moving flows is notorious; the
left turn also must be approached with great care.
Impact from behind on the A78 is contributed to by proximity of
the A78 bend to the south, and could affect


a slow-moving vehicle having turned left onto A78
a vehice slowly turning off the A78 onto the Thirdpart
Road
Possible Outcomes
Collision with other vehicle - also
possible with a cyclist or pedestrian)
Vehicle runs off the road, through
fence
resulting in
Driver misjudges the speed of the 2 approaching traffic flows,
and proceeds when unsafe to do so
Driver tries to turn without first stopping, leading to error of
judgement; may miss his gear change / stalls
Leaving the A78
Driver misjudges speed of approaching A78 traffic
Driver obliged to stop on A78 and wait for pedestrian or
cyclists to clear the junction
+ there is no right turn filter lane for traffic leaving the A78
at the junction (the carriageway is not wide enough for this)
Generally
+ the presence of slower moving agricultural traffic and
‘horse-box’ traffic
Possible Consequences: Near
miss, injury, death
Joining the A78
+ the narrowness of the A78 carriageway reduces margins
for error
+ the presence of cyclists, pedestrians and equestrian
users; the junction has an A78(T) pavement to left and right.
Relative Likelihood: High
Driver unfamiliar with the hazards in this area may be caught
out by behaviours of familiar drivers.
Near miss, Injury , Death
Relative Likelihood
For the possible events shown, the
relative likelihood is categorised as
Higher
Hazard Area 5
Risk: Level 8,
Very serious
Possible Outcomes
Hazard Area, Contributing Factors, Margin for Error,
Hazard Area Ranking
Possible Events
Relative Likelihood
Hazard Area
Risk Level
Manageability
+ the slow tight turn for traffic turning left off the A78
+ the bell-mouth at the junction allows for vehicles to turn
smoothly, but the narrowness of the Thirdpart road does
not allow for 2 vehicles to pass in the immediate vicinity of
the junction. Consequently longer vehicles entering the
Thirdpart road are required to wait on the A78 to allow an
exiting vehicle to clear the junction.
+ on top of the foregoing is the application of the national
speed limit – 60 mph for cars
Margin for Error: Very Low
Hazard Area 5 Ranking: Level 8, Very Serious
Hazard Management and Mitigation
Contributing Factors
Hazard Area
Hazard Ranking
Margin for Error
Risk Level
Singly and in combination
Controllable Variables / Road
Management Options
Pros / Cons
Suggested Best-Fit
Hazard Area 1: Kilruskin Rd / A78 junction
Refer to photos: 4, 5 & 6
Joining the A78 from Kilruskin Road
Margin for Error: Low
Hazard Area 1 Ranking: Level 5, Significant
+ the line of sight to the left (south) only
opens up when about 5m from the junction
edge
Change junction status and
signage to STOP
Hazard Area 1 Risk: Level 5, Significant
+ the junction is Give Way rather than Stop
Reduce A78 speed limit to 50mph
for cars
+ traffic joining the A78 has to negotiate 1 or
2 fast-moving traffic flows
+ driver may intend turning without first
stopping at the junction
Introduce no overtaking double
white lines for 250 yard interval
centred on the junction
Change junction to a STOP
status
These 3 measures
taken together are seen
as delivering a
significant improvement,
cost-effectively
and
Reduce A78 Speed limit to
50mph for cars
and
Introduce no overtaking double
white lines for 250 yard interval
centred on the junction.
+ There is no restriction on overtaking on
the A78
+ The A78 here sees significant numbers of
recreational cyclists
Introduce cycle lanes?
Would reduce
carriageway width and
associated margin for
user error
Turning right from A78 into Kilruskin
Road
Reduce speed limit on A78 to
50mph
The above 3 measures
would mitigate the risks.
+ Driver must cross fast-moving A78 southbound traffic
Introduce right turn filter lane
A filter lane would be
expensive
+ Driver has no right-turn filter lane
With no overtaking and a
reduction of the speed limit, a
degree of mitigation for cyclist
risk is achieved.
The above 3 measures are seen
as likely to deliver sufficient risk
mitigation
Contributing Factors
Hazard Area
Hazard Ranking
Margin for Error
Risk Level
Singly and in combination
Hazard Area 2: Partially blind transition and
straight interval of A78 from just south of
Kilruskin T-junction along to just north of right
turn onto Hunterston Estate Road.
+ For a driver heading south, there is a blind
interval of road in the transition between the
curved and straight sections, more
pronounced to the driver’s right side of road
See Photos 7 – 10, & 13
+ Encountering an overtaking driver –
maybe impatient - and who makes a
misjudgement
Margin for Error: Low, sometimes none
Hazard Area 2 Ranking: Level 7, serious
Hazard Area 2 Risk: Level 7, Serious
Controllable Variables / Road
Management Options
Reduce A78 speed limit to 50mph
for cars
Pros / Cons
Inexpensive and
practical
Extend the A78 No Overtaking
lines to 100 yards north of the
Hunterston Estate junction –
applies to both directions – see
also Hazard Areas 3 and 4 below
Reduce the speed limit for cars
to 50mph
and
+ The national speed limit of 60mph for cars
+ The zero margin for error associated with
vehicles passing in the presence of a cyclist
Widen the road
Ban overtaking
Introduce a suitable cycleway
These are seen as
expensive / unrealistic,
and not the best way to
mitigate the hazards
+ The introduction of a sudden need to
brake, coming from traffic appearing from the
Kilruskin junction, the Hunterston estate
junction, the B782 junction, or over the blind
brow at Highthorne – or from the lay-by
Hazard Area 3: Hunterston Estate Road
Junction and adjacent interval of A78
+ traffic joining the A78 has to negotiate 1
or 2 fast-moving traffic flows
Reduce the A78 speed limit to
50mph
Refer to photos: 10 - 13
+ the junction’s proximity to the B782
junction, at which point overtaking is
permitted for north-bound A78 traffic; the
blind brow contributes to this hazard
Improve the marking s and
signage associated with the
junction, including a STOP sign
Hazard Area 3 Ranking: Level 7, Serious
Hazard Area 3 Risk: Level 7-, Serious
+ its position in the A78 south-bound
overtaking zone
(the 7- refers to the low usage of the Estate
Road)
+ the junction is not sign-posted on the A78
+ there is no right turn filter lane for traffic
Improve marking and signage at
Hunterston Estate Road junction
(see Hazard Area 3 below)
and
Extend the A78 No Overtaking
lines to 100 yards north of the
Hunterston Estate junction –
applies to both traffic directions –
see also Hazard Areas 3 and 4
below
(Initial speed measurements
show a mean speed slightly
below 50mph; more work will be
done on this)
+ The compounding of these scenarios
when a traffic flow in one direction meets a
similar scenario approaching from the
opposite direction.
Margin for Error : Very Low
Reducing speeds over 50mph,
and tighter controls on
overtaking are seen as key
steps.
The recommendations are:
+ The relative narrowness of the
carriageway
+ The low margin for error associated with
speed and narrow carriageways
Suggested Best-Fit
Extend the A78 No Overtaking
lines to 100 yards north of the
Hunterston Estate junction –
applies to both traffic directions –
see also Hazard Areas 2 and 4
Stopping overtaking on
the A78 at this junction,
along with a 50mph
speed limit are seen as
key mitigation
possibilities
These steps are not
expensive
Reduce A78 speed limit to
50mph for cars
and
Change junction to a STOP
and
Improve the marking s and
signage associated with the
junction
and
Contributing Factors
Hazard Area
Hazard Ranking
Margin for Error
Risk Level
Singly and in combination
leaving the A78 at the junction (the
carriageway is to narrow to have one)
Controllable Variables / Road
Management Options
Pros / Cons
Suggested Best-Fit
Road widening?
Widening the road to
allow for a right turn
filter lane on the A78 is
not seen as preferable
to the 3 steps shown
above – and would be
relatively expensive.
Extend the A78 No Overtaking
lines to 100 yards north of the
Hunterston Estate junction –
applies to both traffic directions –
see also Hazard Areas 2 and 4
These 3 single
measures address all
contributing factors
effectively, and
economically
Use the available land to install a
roundabout
+ the absence of clear markings and
signage at the junction
+ the narrowness of the A78 carriageway
reduces margins for error
+ a footway / cycleway crosses the
Hunterston Estate Road just short of the
A78, obliging drivers turning off the A78 to
yield to cyclists / pedestrians
+ on top of the foregoing is the application
of the national speed limit – 60 mph for cars
Hazard Area 4: B782 T-junction and
adjacent intervals of A78
+ traffic joining the A78 has to negotiate 1
or 2 fast-moving traffic flows
Introduce a roundabout, using the
existing open ground
Refer to photos: 12 – 17 & 24
+ the partially blind brow at the north side of
the junction results in limited lines of sight
along the A78 to the north when joining from
the B782 – until almost at the junction edge
Reduce the A78 speed limit to
50mph
Margin for Error: Very Low
Hazard Area 4 Ranking: Level 8, Very
Serious
Hazard Area 4 Risk: Level 8, Very serious
Photo 15: Highthorne Junction looking north
along A78; front of car 2m from junction edge
+ Correspondingly, the junction is partly
obscured from about 160 yards to the north;
and the junction’s visibility on the approach is
not prominent
+ the partially blind brow at the north side of
the junction results in A78 traffic
approaching from the north being blind to
Extend the A78 No Overtaking
lines to 100 yards north of the
Hunterston Estate junction –
applies to both traffic directions –
see also Hazard Areas 2 and 3
and
reduce the speed limit on this
interval of the A78(T) to 50 mph
for cars
and
Extend the A78 No Overtaking
lines to 100 yards north of the
Hunterston Estate junction –
applies to both traffic directions –
see also Hazard Areas 2 and 3
Contributing Factors
Hazard Area
Hazard Ranking
Margin for Error
Risk Level
Singly and in combination
traffic approaching the junction from the
south – and vice-versa
+ the status of the junction as Give Way
instead of Stop
+ the overtaking restriction for north-bound
traffic is lifted at the junction
+ there are no turning filter lanes for traffic
leaving the A78 at the junction (the
carriageway is not wide enough for these,
although the land is there)
Controllable Variables / Road
Management Options
Re-contour the A78 to north to sort
out the blind brow
Pros / Cons
-
Suggested Best-Fit
and
as an interim measure
Introduce a right turn filter lane for
traffic leaving the A78
Change Junction to STOP status
Broaden the carriageway
With a VAS saying
All these are expensive options
which would not necessarily
achieve the safety improvement
STOP, LOOK
+ the width of the A78 carriageway reduces
margins for error
+ the presence of cyclists, pedestrians and
equestrian users
+ on top of the foregoing is the application
of the national speed limit – 60 mph for cars
Hazard Area 5: Thirdpart junction and
adjacent intervals of A78
+ the absence of clear markings and
signage for the junction
Reduce the A78 Speed Limit to
50mph
Refer to photos:18 - 27
+ traffic joining the A78 has to negotiate 1
or 2 fast-moving traffic flows
Improve line of sight to south from
the Thirdpart Road
+ traffic joining the A78 has very restricted
line of sight along the A78 to the south –
which opens up only when car is 2 yards
from carriageway edge
Change status of junction from
Give Way to Stop
Margin for Error: Very Low
Hazard Area 5 Ranking: : Level 8, Very
Serious
Hazard Area 5 Risk: Level 8, Very serious
+ the status of the junction as Give Way (?)
instead of Stop
+ its proximity to the dogleg bend to the
south – 175 yards, which equates to the 55
mph wet-road stopping distance; and to the
B782 T-junction to the north
+ the narrowness of the A78 carriageway
Introduce a SLOW DOWN VAS in
this vicinity of the A78
This set of measures is
seen as cost-effective
and practicable to
address the most
serious features of this
junction
Reduce Speed Limit on this
interval of the A78(T) to 50 mph
and
Improve line of sight to south
from the Thirdpart Road
and
Change status of junction from
Give Way to Stop
Improve markings and signage
associated with this junction
and
Improve the bellmouth and the first
short interval of Thirdpart Road
Introduce a SLOW DOWN VAS
in this vicinity of the A78
and
Improve markings and signage
Contributing Factors
Hazard Area
Hazard Ranking
Margin for Error
Risk Level
Singly and in combination
reduces margins for error
+ there is no right turn filter lane for traffic
leaving the A78 at the junction (the
carriageway is not wide enough for this)
+ the presence of cyclists, pedestrians and
equestrian users; the junction has an A78(T)
pavement to left and right.
+ the presence of slower moving
agricultural traffic and ‘horse-box’ traffic
+ the slow tight turn for traffic turning left off
the A78
+ the bell-mouth at the junction allows for
vehicles to turn smoothly, but the
narrowness of the Thirdpart road does not
allow for 2 vehicles to pass in the immediate
vicinity of the junction. Consequently longer
vehicles entering the Thirdpart road are
required to wait on the A78 to allow an
exiting vehicle to clear the junction.
+ on top of the foregoing is the application
of the national speed limit – 60 mph for cars
Controllable Variables / Road
Management Options
Widen the A78 to allow filter lanes
for turning off the A78
Pros / Cons
This is seen as too
expensive when
compared to the
suggested set of
changes
Suggested Best-Fit
associated with this junction
and
Improve the bellmouth and widen
the first short interval of Thirdpart
Road