Research Project

Estimating risk to road users and impact of active traffic calming measures on vehicular speed in highway work zones

Geetam Tiwari

Project Details

ABSTRACT

The focus of this study is safety of workers and road users especially vulnerable road users
(pedestrians, bicyclists, motorcyclists, etc.) present on highway work zones in India which includes
the activities of Pillar 2 “Safer Roads and Mobility” considered under one of the five pillars of road
safety as described in the Decade of Action Plan. 
In the past, very few studies have been done to understand the special requirements of work zone safety
both for the road users and workers present at highway work zones. Rate of fatal crashes has increased
in the past decade as the National Highways Authority of India has embarked upon an ambitious programme
of expanding the highway network. IIT Delhi conducted a safety audit on Lucknow-Muzzafarpur National
Highway in India and found the current guidelines of managing the highway work zones inadequate. 
The proposed study aims at contributing to the development of guidelines for controlling speeds at
highway work zones. The experiments are designed to estimate the effectiveness of passive (colour and
shape of signs) and active speed control measures (traffic calming). The objectives of the study are:
1) to determine the speed characteristics of vehicles in highway work zones before and after the
installation of Active traffic calming measures. 2) to determine the characteristics of and
distribution of fatal crashes within highway work zones and risk to workers and road users and compare
the differences of the distributions of work zone crashes and non-work zone crashes.
 The results of the study are expected to provide inputs into revision of existing guidelines and codes
available for work zone safety and formation of new standards/guidelines for improving the safety at
highway work zones in low and middle income countries like India.

BACKGROUND

The importance of safety within road work zones has been recognized at International level. Crash rates
on highway work zones have been found to be higher than other locations in many countries like U.S.
(Garber and Zhao, 2002), New Zealand (Leland Jr and Allpress, 2010). This is an important consideration
for India since government has launched a major highway expansion programme of Golden Quadrilateral
project covering 5,846 km length. A recent study of NH-28 in India shows the inadequacy of current
traffic management and safety practices at highway work zones.

OBJECTIVE

The objectives of the study are to 
a)Determine the speed characteristics of vehicles in Advance Warning Zone (AWZ), Working Zone (WZ) and
Terminal Transition Zone (TTZ) before and after the installation of Active traffic calming measures
like Rumble strips on highway work zones. 
b)Determine the characteristics of and distribution of fatal crashes within highway work zones, study
these distributions with respect to different time periods, single and multiple vehicle involvement,
heavy vehicle involvement, and compare the differences of the distributions of work zone crashes and
non-work zone crashes. 
c)Estimate risk to different road users and workers at highway work zones 
d)Recommend possible effective countermeasures as a result of the aforementioned analysis to modify
current guidelines. 

CONCLUSION AND RECOMMENDATION

a)All vehicle type universally follow the pattern of a drop in speeds to near or below 30 km/h as they
approach rumble strips 
b)Pattern followed by the vehicle type – Car shows that most of them move between mean speed of 40km/h
and 50 km/h in WZ in the presence of rumble strips 
c)Trucks travel between mean speed of 30 km/h and 40 km/h and Motorized 2-wheelers move between 40 km/h
and 45 km/h.
d)Vehicles reduced their speeds 50m before and after the Rumble strips. However there is a tendency to
speed up after 50m 
e)Mann-Whitney U test results show that there is a significant difference in the speeds of M2W, Car,
LCV and Truck at Km 162 (only passive measures) and Km 168 (both active & passive measures). Also,
there is a significant difference in the speeds of all vehicle type at Km 144 (50mm high rumble strips)
and Km 168 (25mm high rumble strips), .i.e., as the height increases, the speeds of vehicles decrease
f)Height of Rumble strips plays an important role in reducing speeds of vehicles
g)50 mm high rumble strips were more effective than 25mm rumble strips in reducing vehicle speeds
h)Pedestrians and motorized two-wheeler riders accounted for 40% and 30% of all traffic fatalities
respectively
i)Largest proportion of fatalities (54%) for all road user categories are associated with impact with
trucks 
j)48% of fatalities occurred among 26-60 years age group (working age group)
k)40% of the fatal accidents were “Hit pedestrians” followed by Rear End collisions (36%)
l)Truck fatalities are relatively high at 3-4 PM whereas Pedestrian fatalities peak around 7 AM and 8
PM.


 

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