SR4S (Star Rating for Schools) has been used by partners in 63 countries to assess the risk children are exposed to on their school journeys. iRAP is now updating the SR4S model, under the guidance of iRAP Global Technical Committee, to ensure SR4S reflects the latest research, evidence and experience of partners around the world using the tool. SR4S uses iRAP’s Pedestrian model to rate the safety of road infrastructure, and the SR4S model update is part of a broader review of iRAP models which will be implemented towards the end of 2023.
The SR4S model update is consistent with the Safe System principles guiding that vehicle speeds should not exceed 30km/h where vehicles and pedestrians mix. The review considered these principles and feedback of partners using the SR4S to assess more than 1,000 schools, and identified several enhancements that could be made to the assessed road attributes and its risk factors. Speeds are now recorded in 5km/h increments, and traffic flow increments of 1,000 vehicles per lane up to 20,000 vehicles per lane have been introduced. Risk factors for sidewalks, paved shoulders, number of lanes, lane width, property access points, pedestrian crossing facility, pedestrian crossing quality, intersection type, median type, vehicle flows, intersecting road volume, and pedestrian channelization have been introduced or revised.
In practice, the model’s results will be more rigorous, and achieving a 3-star or better rating for a location may require the combination of more safety elements and lower speeds compared to the previous version of the model. Users’ experience with the actual data collection process and the use of the SR4S tools will remain largely the same though. The enhancements also include the introduction of decimal star ratings, which will allow users to see safety improvements within a same Star Rating band. This feature will provide more granular information on the safety rating of a location, enabling better decision-making.
Star Rating for Schools Global Programme Coordinator Rafaela Machado is delighted with the new enhancements, “The SR4S programme has been developed in consultation with a fantastic network of Lead Partners. Their inputs have been guiding the SR4S tools, and now we are excited to also announce this model enhancement. This update reflects the experience of partners using the SR4S to assess more than 1,000 schools and, along with the new SR4S and YEA apps, will ensure partners continue having access to evidence-based tools to support their school safety programmes.”
What you need to know now…
- We will be making the enhancements in June – we will advise on the exact time and date closer to the day – with at least 3 weeks’ notice. We will be making the enhancements in June– we will advise on the exact time and date closer to the day – with at least 3 weeks’ notice. We want to make sure you have enough time to plan your projects and are aware of the deployment day of the new model.
- After the model update is deployed, any new assessments created in the SR4S platform will be automatically generated using the new model. Previous data in the SR4S system will not be automatically reprocessed using the new model, but users will be able to update it as well if they wish to. It will be important any before and after upgrade results at individual locations are calibrated to the new model for accurate analysis of the safety change.
- If you have an ongoing project and needs support with managing your results, please get in contact with [email protected] and we will be happy to support you.
- We will launch an updated SR4S video course in June and we recommend SR4S app users take a look as a refresher before using the new model, but it will not be mandatory.
- There is a comprehensive Frequently Asked Questions (FAQ) document now available ici or refer to information below (under video). If you have any further questions, please do not hesitate to contact us at [email protected]. For more information on the model review, you can also access the report 2022 Vehicle Speeds and the iRAP Protocols: A Review.
- If you don’t yet receive the SR4S newsletter and would like to stay abreast of our innovation and partner successes making school journeys safer world-wide, sign up here.
FAQs on the SR4S model update – April 2023
Why are you updating the SR4S model?
As part of our commitment to ensure that SR4S reflects the latest research, evidence and experience our partners in using SR4S around the world, we conducted a review of the model that underpins SR4S. As a result of the review, we have identified a number of enhancements that can be made. This review was performed under the guidance of the iRAP Global Technical Committee.
What Safe System principles underpin SR4S?
According to Safe System principles, vehicle speeds should not exceed 30km/h where vehicles and pedestrians mix. This is the tolerable speed in the event that a conflict between vehicle and pedestrians occurs, giving time for the vehicle to stop or to significantly reduce its speed and the energy associated with the impact. SR4S helps measure, monitor and communicate the risk children are exposed to on a school journey. We know that the behaviour and physiologically of children makes them highly vulnerable on the roads.
For the SR4S model review, these Safe System principles were considered as follows:
- A road without crossings or sidewalks should not achieve 5 Stars where vehicle speeds exceed 30km/h.
- It should not be possible to achieve 5-Stars while having to cross multiple traffic lanes in each direction without a crossing facility.
- 3-Star roads without pedestrian facilities should not be 40km/h or above.
What are the main effects of the enhancements?
The star ratings will be calculated on largely the same road attributes as before; however, several sets of risk factors that underpin the Star Ratings have been updated. This means that the total scores for the risk in each location will change, which may result in a different star rating result. Now different combinations of road elements may be required for a 4 or 5-star location, for instance. In general, the new results will be more rigorous, and in order to achieve 3 star or better for your locations you may need the combination of more safety elements and lower speeds compared to the previous version of the model.
What are the main enhancements that are being made?
The main enhancements that are being made to the SR4S model are:
- Speeds: the underlying risk factors have been adjusted and speeds may now be recorded in 5km/h (or 5 mph) increments starting from 0km/h (or 0mph).
- Traffic flows: introduced new risk factors for traffic flow increments of 1,000 vehicles per lane up to 20,000 vehicles per lane.
- Sidewalks: new risk factors have been introduced which reflect the new speed and traffic flow risk factors.
- Number of lanes: risk factors have been introduced for Pedestrian Along crashes, increasing risk as the number of lanes does.
- risk increases as the number of lanes does.
- Paved shoulders: risk factors have been revised as part of the new sidewalk risk factors. Risk factors for paved shoulders previously only came into effect in the absence of a sidewalk. A notable change is that the risk factors for paved shoulder 0-1m wide are now equal to that of no facility.
- Lane width: lane width risk factors for the along crash types relate to vehicle run-off have been adjusted for rural roads, where they apply only to shoulder facilities (paved shoulders 1-2.4m and >2.4m). Urban risk factors have been removed as evidence of risk for pedestrians and bicyclists did not support the current risk factors.
- Property access points: property access is now considered in the Along crash type, which better represents the risk of vehicles moving in and out of driveways to pedestrians, irrespective of whether there is an intersection present.
- Pedestrian crossing facility: new risk factors have been introduced which reflect the new speed and traffic flow risk factors, including when operating speed surpasses acceptable thresholds; new category for unmarked crossings introduced.
- Pedestrian crossing quality: new combined risk factors for poor quality grade-separated crossings (e.g. bridges).
- Intersection type: risk factors amended to better account for crossing distance.
- Number of lanes, lane width and paved shoulder width: new risk factors that account for the combined effect of number of lanes, lane width and paved shoulder width for the overall crossing distance for pedestrians.
- Median type: pedestrian crossing risk factors related to median type have been removed (except for one-way roads). Where a median functions as a refuge, this is now recorded as the pedestrian crossing type with a refuge (i.e. change to coding rules).
- Vehicle AADT: conditional AADT per lane pedestrian factors have been updated so they now apply for roads with no facilities, unmarked crossings and crossings with refuges only.
- Intersecting road volume: new risk factors introduced to allow high traffic flows on side roads to be recorded.
- Pedestrian channelization: update of pedestrian fencing impact on pedestrian crossing flows and its combination with grade separated crossings.
- Decimal stars: new type of presentation indicating the scale of star rating within the same band.
- Star Rating bands: adjustment of the star rating thresholds to accommodate new risk factors and the Safe System principles.
What are decimal star ratings?
Currently, a simple star rating is calculated for each location assessed with SR4S. With the decimal star ratings, it is possible to see where in the band the rating is. For example, a star rating of 3.5 stars indicates that it is in the middle of the 3-star band, while a star rating of 3.9 stars indicates that it is at the top of the star rating band.
Where can I find more technical information about the review and enhancements?
If you would like to learn more about the updates made to the model, access our methodology page and the detailed report – irap.org/research-and-technical-papers/
Are my existing star ratings going to change?
Any existing assessment results produced using the previous model will not be automatically changed in the system. You will have the option to keep your results as they are or update them to the latest model version once it is available. We will be happy to further discuss your special needs on managing your data and performance tracking.
Does the process of coding the data change?
The model update will result in relatively few changes to the way of coding some road attributes, for example:
- Sidewalks – pedestrian facility separation from the road measurement. The distance of sidewalks should now be recorded from the edge of the roadbed or the curb, not the edge of the driven lane. Paved shoulders are now factored in as providing added buffer if present.
- Sidewalks – poor and moderate quality sidewalks. New coding guidance is being provided for poor quality and moderate quality sidewalks.
- Pedestrian crossing facility: refuges on roads with medians. Where there is a road with a median that also functions as a pedestrian refuge, this is now recorded as the pedestrian crossing type with a refuge.
Can I compare results from the old and new models at a particular location?
Please make sure to compare pre- and post-intervention assessment using the same model version. We will provide you a disclaimer explaining the model review and any implications in the results. If you conducted your pre-intervention assessments with an older version of the model, it may happen that your post-intervention assessments may generate star ratings lower than your first assessments. In this case, we would advise you to update your pre-intervention assessments to the new model. This will make your assessments before and after comparable. We will also provide a disclaimer that can be used in your reports and presentations informing the version of the model with which your assessments were performed. Feel free to get in contact if you need any assistance to manage your data.
Do I have to update my star ratings?
You can keep your previous assessments saved in the SR4S and no updates to the new model are required. If you plan to publish your results, however, you will be required to update your assessments to the latest version of the model.
Can I still use the previous model version for my assessments?
No. After the model update is deployed, you will be required to use it for any new assessments created in the SR4S platform.
Why is it harder to achieve 3-stars or better now?
Based on the latest research and principles of Safe System, bold measures should be taken in terms of road design and speed management to ensure pedestrian safety. Humans, especially children, make mistakes when using the road. For this reason, risk factors have been updated to reflect the real behaviour of all road users, and these lead to a rigorous assessment of risk. This new model was tested in multiple SR4S locations to ensure consistency with these principles and to meet feedback from partners using the tool in more than 60 countries.
Does that mean that assessments with the old model were wrong?
No. The previous and the updated models represent a proactive approach to road safety that can be used to measure, monitor and communicate the risk for pedestrians. It is natural that as experience is developed and new research and evidence reviewed, updates to the model will incur. In some specific situations in the past, partners experienced star ratings that were not necessarily consistent with what they perceived, based in evidence and experience, to be the actual level of safety. This feedback, combined with a review of the latest research and evidence, has been valuable in improving the models.
When is the next model review?
The Global Technical Committee oversees our models and advises about any needs for updates on a regular basis. This update to the model represents an important and improvement and at this point there is no plan to conduct a further report in the short to medium term.
Is there any action required from me?
After the model update is implemented, you will be notified by email. If you have any ongoing project and needs support with managing your old and new results, please get in contact with [email protected] and we will be happy to support you. If you need to compare your old data and new assessments, please let us know and we will help you update your previous assessments and manage your results. In 2023, we are launching an updated SR4S video course, we would suggest you take a look as a refresher before using the new model.