ENG H191 Hands-on Laboratory
Lab 2: Spot Speed Study
Objective and Purpose:
A spot speed study is conducted to determine speeds of vehicles passing a point. It is useful in evaluating:
Aspects of the geometric design of highways (curvature, grade, super-elevation),
Application of traffic control devices (sight distance, no passing zones, speed limits, traffic-sign location),
Accident locations,
Effectiveness of traffic improvements (additional lanes, lane widening),
Needed enforcement.
Data Collection:
In this lab, you will collect and analyze speed data associated with a specific location on
Woody Hayes Drive or Olentangy River Road that passes beneath Woody Hayes Drive. You will need a stopwatch in order to time vehicles as they pass through a measured “speed trap”.
You will use a simple "Field Sheet" like that in Figure 7-5 of the lab handout to record the raw data. The speed trap will be 176 feet in length. The locations for the studies are:
A.
On Woody Hayes Drive – West of Bridge over Olentangy River Road, East Bound
Traffic
B.
On Woody Hayes Drive – Bridge over Olentangy River Road, West Bound Traffic
C.
On Woody Hayes Drive – West of Bridge over Olentangy River Road, East Bound
Traffic
D.
On Woody Hayes Drive – Bridge over Olentangy River Road, West Bound Traffic
E.
On Olentangy River Road – Below and South of Woody Hayes Bridge, South Bound
Traffic
F.
On Olentangy River Road – Below and South of Woody Hayes Bridge, North Bound
Traffic
G.
On Olentangy River Road – Below and South of Woody Hayes Bridge (slightly more south of station E), South Bound Traffic
H.
On Olentangy River Road – Below and North of Woody Hayes Bridge, North Bound
Traffic
I.
On Olentangy River Road – Below and South (slightly more south of station F)
Woody Hayes Bridge, North Bound Traffic
Collect your data while standing well back from the road. Do not stand in the road. Safety is a major concern. THINK ABOUT WHAT YOU ARE DOING.

Data Analysis:
After collecting the speed data, create a frequency distribution table as shown in Table 7-2 of the lab handout. Create 2-mph speed groups depending on your collected speeds. After creating the table, make two graphs of your data, a frequency distribution curve (bell curve, Figure 7-6 of lab handout) and a cumulative frequency curve (S curve, Figure 7-6 of lab handout). It is important that you create these 2 graphs as a single figure with the speed axis being the same scale for both.
They are inter-related as can be seen in Figure 7-6 of the lab handout.
From the graphs determine:
Mode
10 mph pace
% Vehicles in the pace
85 th
Percentile speed
Median speed
Estimated standard deviation
Also, calculate the following:
Average speed
Standard deviation
Compare your calculated standard deviation with the estimated standard deviation from the graphs.
Collect your data while standing well back from the road. Do not stand in the road. Safety is a major concern. THINK ABOUT WHAT YOU ARE DOING.