Star Ratings
Star Ratings are an objective measure of the level of safety which is ‘built-in’ to the road through more than 50 road attributes that influence risk for vehicle occupants, motorcyclists, bicyclists, and pedestrians. Star Ratings reflect the risk as it relates to an individual road user. 1-Star roads have the highest risk and 5-Star roads the lowest risk.
Star Ratings have the following capabilities,
- can be produced without reference to detailed crash data.
- can be produced for all types of roads including low volume rural roads.
- are used for road safety inspection, road safety impact assessments, and in designs.
Star Ratings are prepared for four road user groups viz. vehicle occupant, motorcyclist, pedestrian and bicyclist. A road constructed with features that affect safety of vehicles but lacking in safe infrastructure for VRU’s like pedestrian may get 3-star or better for vehicles and 1-or 2-star for pedestrian.
Safer Roads Investment Plans (SRIPs)
Safer Roads Investment Plan gives list of safety treatments on basis of economic analysis as a solution to improve safety of the assessed road. SRIPs utilize the data and analyses from Star Ratings to propose targeted interventions aimed at improving road safety. These plans consider over 90 proven road improvement options such as improvement in road markings and signage, traffic calming measures, low-cost footpath, pedestrian crossings, streetlights, etc. Each proposed measure is evaluated for its cost-effectiveness and potential impact on reducing fatalities and serious injuries, ensuring that the investments made are both practical and beneficial in enhancing road safety of the low volume rural roads.
iRAP assessment for LVRR
iRAP’s Star Ratings and Safer Roads Investment Plans (SRIPs) are crucial in identifying and quantifying road safety interventions that lead to significant reductions in road fatalities and serious injuries. The process starts with road surveys using off-the-shelf camera with built-in GPS which can be fixed quickly on any car or vehicle, followed by data coding of more than 50 road attributes at 100-meter intervals, and concludes with detailed analyses using the iRAP software (ViDA) to produce star ratings and investment plans.
The data collection and analysis process can be quicker and low-cost with the following customization for low volume rural roads,
- The only survey equipment required is a small camera with built-in GPS (like GoPro) that can be fixed on any car or vehicle
- Speed measurement with a hand-held radar gun on sample basis (duration 1hr) at few survey locations
- Traffic count by manual method for duration of 1hr at few survey locations, if AADT data is not available
- Road attribute coding (extraction of required road features data by viewing the video survey images) can be quicker as certain features are not applicable for low volume rural roads (details given in the table at the end of this article)
Safer Roads Investment Plan to focus on low-cost interventions relevant to rural roads. Some treatments which are more relevant to highways or high-volume roads such as road widening, four-laning, physical median, grade separated intersection, foot-over bridge, etc. are switched-off while processing.
Benefits of iRAP assessment of LVRR:
Enhanced Safety: Each improvement in star rating is associated with a halving of crash costs, which is vital for roads where even minor incidents can have disproportionately high impacts due to isolated locations and lack of immediate medical services.
Cost-Effective Interventions: The iRAP methodology helps prioritize interventions that offer high returns on investment in terms of safety per dollar spent. For rural roads, where funds are limited, ensuring the most effective use of resources is critical.
Sustainability: Unlike traditional road safety audits which are qualitative, Star Ratings provide a quantitative and systematic assessment that can guide long-term infrastructure improvements.
Specific Recommendations for LVRR using Star Rating:
Adapting to Low Traffic Volumes: Star Ratings assessment factor in the specific characteristics of LVRR, such as their lower traffic volumes and higher rates of non-motorized users.
Cost-Effective Infrastructure Changes: Interventions like improved road markings, installation of rumble strips, and basic signage can significantly enhance safety at a relatively low cost. These are especially beneficial in rural areas where high-cost solutions are not feasible.
Community Engagement: Engaging local communities in the safety assessment process can help tailor the interventions to meet local needs effectively, fostering greater community support and ensuring maintenance.
Example of Star Rating on a low-volume rural road
Road attributes to be recorded in the process of generating Star Ratings
The process of recording road attributes for Low-Volume Rural Roads (LVRR) involves fewer attributes, thereby speeding up the process and saving time and resources. The table below illustrates features typically applicable to LVRRs, while the third column highlights features more relevant to highways and urban roads. The coding process is flexible, allowing exceptions to code additional features when necessary.
| Road attribute category | Features applicable for LVRR | Features not applicable for LVRR |
| Carriageway | Undivided road | Carriageway A of a divided road Carriageway B of a divided road Carriageway A of a motorcycle facility Carriageway B of a motorcycle facility |
| Land use – left and right side | Educational Commercial Industrial and manufacturing Residential Farming and agricultural Undeveloped areas Not Recorded | |
| Area type | Urban Rural | |
| Speed limit | Value in kmph | |
| Median type | Centre line Wide centre line (0.3m to 1m) Central hatching (>1m) Flexible posts | Physical median width 0 to <1m Physical median width 1 to <5m Physical median width 5 to <10m Safety barrier – concrete Safety barrier – metal Safety barrier – motorcycle friendly Safety barrier – wire rope Physical median width 10 to <20m Physical median width >=20m One way |
| Centreline rumble strips | Not present | Not present Present |
| Roadside severity – distance left and right side | 0 to <1m 1 to <5m 5 to <10m >=10m | |
| Roadside severity – object type left and right side | Type of object | |
| Shoulder rumble strips | Not present | Not present Present |
| Paved shoulder – left and right side | None Narrow (≥ 0m to < 1.0m) | Medium (≥ 1.0m to < 2.4m) Wide (≥ 2.4m) |
| Intersection type | 4-leg unsignalised with no protected turn lane 3-leg unsignalised with no protected turn lane Railway Crossing – passive (signs only) Railway Crossing – active (flashing lights / boom gates) None | Roundabout 4-leg unsignalised with protected turn lane 4-leg signalised with no protected turn lane 3-leg unsignalised with no protected turn lane 4-leg signalised with protected turn lane 3-leg unsignalised with protected turn lane 3-leg signalised with protected turn lane Merge lane Median crossing point – informal Median crossing point – formal |
| Intersection channelisation | Present Not present | |
| Intersecting road volume | 100 to 1,000 vehicles 1 to 100 vehciles Not applicable | ≥15,000 vehicles 10,000 to 15,000 vehicles 5,000 to 10,000 vehicles 1,000 to 5,000 vehicles |
| Intersection quality | Poor Adequate Not applicable | |
| Property access points | Commercial Access ≥1 Residential Access ≥3 Residential Access <3 None | |
| Number of lanes (per direction of travel) | One | Four or more Three Three and two Two Two and one |
| Lane width | Narrow (≥ 0m to < 2.75m) Medium (≥ 2.75m to < 3.25m) | Wide (≥ 3.25m) |
| Curvature | Very sharp Sharp Moderate Straight or gently curving | |
| Quality of curve | Poor Not applicable Adequate | |
| Grade | ≥ 10% ≥ 7.5% to <10% ≥ 0% to <7.5% | |
| Road condition | Poor Medium Good | |
| Skid resistance / grip | Unsealed – poor Unsealed – adequate Sealed – poor Sealed – medium Sealed – adequate | |
| Delineation | Poor Adequate | |
| Street lighting | Not present Present | |
| Pedestrian crossing – inspected road and side road (at intersection) | Unsignalised marked crossing without a refuge No facility Unsignalised raised marked crossing without refuge Raised unmarked crossing without refuge | Grade separated facility Signalised with refuge Signalised without refuge Unsignalised marked crossing with refuge Refuge only Unsignalised raised marked crossing with refuge Raised unmarked crossing with refuge |
| Pedestrian crossing quality | Poor Adequate Not applicable | |
| Pedestrian fencing | Not present Present | |
| Speed management / traffic calming | Not present Present | |
| Vehicle parking | Two sides One side None | |
| Sidewalk – left and right side | Non-physical separation 0m to <1.0m Non-physical separation 1.0m to <3.0m None | Non-physical separation ≥ 3.0m Physical barrier Informal path 0m to <1.0m Informal path ≥ 1.0m |
| Service road | Not present | Not present Present |
| Facilities for motorised two wheelers | None | Inclusive motorcycle lane on roadway Exclusive one way motorcycle path without barrier Exclusive one way motorcycle path with barrier Exclusive two way motorcycle path without barrier Exclusive two way motorcycle path with barrier |
| Bicycle facility | None | Extra wide outside (≥4.2m) On-road lane Off-road path Off-road path with barrier Signed shared roadway Shared use path |
| Roadworks | Major road works in progress Minor road works in progress No road works | |
| Sight distance | Poor Adequate | |
| Vehicle flow (AADT) | Number of vehicles per day | |
| Motorcycle % | % | |
| Pedestrian peak hour flow across, along left and right side of the road Bicycle peak hourly flow | 900+ 501 to 900 401 to 500 301 to 400 201 to 300 101 to 200 51 to 100 26 to 50 6 to 25 1 to 5 0 | |
| Operating Speed (85th percentile) | Value in kmph | |
| Operating Speed (mean) | Value in kmph | |
| School zone warning | No school zone warning School zone static signs or road markings School zone flashing beacons Not applicable (no school at the location) | |
| School zone crossing supervisor | School zone crossing supervisor not present School zone crossing supervisor present at school start and finish times Not applicable (no school at the location) |
