Majma'ah University
Collage of Engineering
Civil Engineering Program
1433 -1434
sheet (3)
First semester
Stream Characteristics
Highway & traffic Engineering
code : CE380
1- Given a 4 lane rural highway with operating speed 60 mph carrying 700 vph in one
direction :
a. Determine the percent of total time that lane change opportunity exists from outside
to inside lane, knowing that the minimum acceptable headway for this maneuver is 2
sec.
b. Determine the average blocked length.
c. If the lane change is due to a slower vehicle traveling at 30 mph ahead in the stream ,
determine the average delay due to this maneuver.
2- A two lane two way rural highway carries 600 vph in each direction . the percent of
blocking time was found to be 94.5% of the total time in one hour, the oncoming vehicle
speed was 40 mph and the overtaking is 25 sec as a minimum headway and the overtaking
vehicle speed was 60 mph . if there were only 30 gaps greater than 25 sec. in duration ,
determine the average delay due to this maneuver.
3- Based on the average spacing of moving vehicle , Calculate the theoretical capacity per
houre per lane if the running speed is 55 mph and the reaction time is 2 sec . Base your
calculations on a passenger car of a 15 ft length.
4- A 2-lane rural highway is to be constructed in a flat area lane width is 9 ft and frequent
obstructions are located within 2.5 ft from only one side of the pavement . sight distance
is less than 1500 ft over 30% of the highway length and 15% of the traffic volume is
medium powered trucks . if operating speed is 45 mph calculate the practical capacity and
the average delay traffic volume that can be accommodated by this highway.
Dr. Mahmoud thrwat Azmi
11\1433
5- Compute the practical capacity for each of the two highways described below knowing
that design speed is 60 mph commercial vehicles are 10% of the total traffic volume and
terrain is mountainous:
a. 2-lane highway with 12 ft , 8 ft shoulders and sight distance restrictions over 20% of
the length.
b. 2-lane on a hilly section (6% grade sustained for a length of 3 miles ) with 11 ft lanes ,
2 ft shoulders, and no sight distance restrictions.
6- An existing 2-lane highway is situated in a rolling terrain with 80% sight distance
restrictions 18 ft pavement practical continuous obstructions within 4 ft of both pavement
edges and 8% trucks .
Design speed is 40 mph and current AADT is 2600. It is expected that AADT will increase to
4100 if this highway is improved Evaluate the existing practical capacity and indicate the
type of improvement (i.e. alignment , cross sections etc…)you suggest to accommodate
the anticipated future traffic volume).
7- A 4-lane divided highway with 10 ft lanes , no shoulders and 10 ft median island was
located in a rolling terrain. If the operating speed is in the range of 40-45 mph and 14%
commercial vehicles are expected to use this highway, calculate the practical capacity.
Determine the percent increase in practical capacity if the lane width is increased to 11 ft ,
8 ft shoulders were provided and commercial vehicles were reduced to 8%.
Dr. Mahmoud thrwat Azmi
11\1433