IndiaRAP uses the globally recognised iRAP Star Rating methodology for infrastructure safety and iRAP protocols to save lives on safer roads. They were developed by the world’s leading road safety researchers and organisations and are independently governed by a Global Technical Committee, informed by the latest research of iRAP Centres of Excellence and with local innovation by partners through iRAP’s Innovation Framework.
Star Rating
Star Ratings involve an inspection of road infrastructure attributes that are known to have an impact on the likelihood of a crash and its severity. Between 1 and 5-stars are awarded depending on the level of
safety which is ‘built-in’ to the road. Star Ratings can be completed worldwide, in urban and rural areas and without reference to detailed crash data, which is often unavailable in low-income and middle-income
countries. The safest roads (4- and 5-star) have road safety attributes that are appropriate for the prevailing traffic speeds. Road infrastructure attributes on a safe road might include separation of opposing traffic by a wide median or barrier or good line-markings.
- Road inspection is conducted to collect video images of the survey road with geo-reference data
- Video images are viewed by trained coders in the office to extract 50+ road attributes for each 100metre road segment
- Along with supporting data like traffic flow (AADT), pedestrian and bicycle flow and operating speeds the road attribute data is processed in ViDA
- ViDA generates Star Rating Score (SRS) for (i) vehicle occupant (ii) motorcyclist (iii) pedestrian and (iv) bicyclist
- Star Ratings for these 4 groups of road users are determined by assigning SRS to predetermined bands
- Road section with lower SRS indicates low risk hence gets better stars (3, 4 or 5 Stars) and that with higher SRS indicates high risk and hence gets poor stars (1 or 2 Stars)
- The Star Ratings are presented in the form of tables, charts and colour coded maps
Safer Roads Investment Plan (SRIP)
A SRIP is prioritised list of countermeasures that can cost-effectively improve Star Ratings and reduce infrastructure-related risk. The plans are based on an economic analysis of a range of countermeasures, which is undertaken by comparing the cost of implementing the countermeasure with the reduction in crash costs that would result from its implementation. The plans contain extensive planning and engineering information such as road attribute records, countermeasure proposals and economic assessments for 100-meter segments of a road network. The plan also gives estimate of how many lives and serious injuries are likely to be saved along with economic analysis, if the suggested treatments are implemented.
- The model selects one or more safety treatments from a list of 90+ such treatments with the selection criteria of benefit-cost ratio. This means for a 100m road segment a combination of treatments may come up in the SRIP based on the infrastructure present at the time of assessment.
- Based on crash studies around the world, reduction in deaths and serious injuries for each 100m segment of road is estimated
iRAP assessment involves recording 50+ road attributes, for every 100m road length, that are known to influence the likelihood and severity of crashes. Road attributes like Median types and number of lanes affect head-on collision risk; lane width, delineation, roadside hazards and road condition affect run-off collision risk; horizontal curvature influences both run-off and head-on collision risk; facilities like footpath, pedestrian crossing and streetlight influence the vehicle-pedestrian collision risk. Supporting data like traffic flow and vehicle operating speed (85th percentile speed) are collected which also influence likelihood and severity of road crash.
How do we consider the local road environment in safety assessments
Star Ratings and Investment Plans prepared for roads in India reflect local conditions, practice and experience with a range of local data such as, crash data, Vehicle operating speeds, Traffic volumes (AADT), Motorcycle percentage in traffic volume, Pedestrian and bicycle flows, Economic cost of life and serious injuries, Countermeasure construction costs, and Discount rate and period for the economic analysis. Processing of data for each road or road network being assessed involves calibration of the model with the historic crash data.
Star Rating Example Images:
The following images illustrate sections of roads, their Star Ratings and the road attributes that influenced the Star Rating. The images represents road sections from the extensive road assessments conducted in India. The images show Star Ratings for vehicle occupant and pedestrian, as these road users account for a significant number of deaths and illustrate typical road layouts. Similar examples for motorcyclists and bicyclists are also available.
In the figures:
These images help to illustrate the fact that the level of risk associated with a road’s infrastructure, and hence its Star Rating, is a function of numerous attributes, including traffic volume and travel speeds
