Star Rating

iRAP Star Ratings are based on road inspection data and provide a simple and objective measure of the level of safety ‘built-in’ to the roads for vehicle occupants, motorcyclists, pedestrians and bicyclists. 5-star roads (green) are the safest, and 1-star (black) are the least safe.

Broadly speaking, every extra star rating increase result in a halving of crash cost in terms of the number of people who are killed and seriously injured. Importantly Star Ratings can be completed without reference to detailed crash data.

New, vision-based ADAS technologies leverage EuroRAP’s expertise in infrastructure-based safety measures, to provide real-time automated assessments through mass vehicle fleet sourced data.

The iRAP Methodology fact sheets answer many of the questions people have about the iRAP approach, covering topics such as crash types, Star Rating Score equations, model calibration and estimation of economic benefits and costs. The ‘iRAP Methodology’ fact sheets describe the Star Rating and Safer Roads Investment Plan methodologies, while the ‘iRAP Road Attribute Risk Factors’ fact sheets describe the risk factors used in the models. 

Please find the relevant information in the iRAP website at and on the RAP Infrastructure Safety Management Tools at

If you have any questions about the iRAP methodology that are not answered in the fact sheets, please contact us. We will be happy to answer your questions.

RAPs and Road Safety Audits and Inspections working together

  • The RAP approach includes an objective, evidence based measure of the safety performance of the road for all road users that can guide policy, standards and performance tracking.  The RAP assessments also include fatality and serious injury predictions and high-level Safer Road Investment Plans that optimise lives saved per unit of investment. iRAP results are often used to deliver broad network level outcomes that provide road authorities and others with risk assessment data and programme costs for high level planning, budgeting and the setting of road safety policy targets.
  • Road Safety Audit is a systematic method of checking the safety aspects of new road improvement schemes. The term is generally considered to refer to a formal independent and multi-disciplinary detailed assessment of the safety performance of all new highway and traffic management schemes, including modifications to existing layouts, and are undertaken at different stages during the design, planning and construction process. The number of countries worldwide adopting Road Safety Audits as a formal procedure is increasing, making a significant contribution to improving highway safety. Road Safety Audits can provide a very detailed level of scrutiny, identifying particular issues and design failings at specific locations that may conform to relevant design standards but nonetheless increase road user risk. Recommendations are based on the knowledge and experience of the audit team.
    A road safety audit is defined as a formal and independent technical check of a road scheme design and construction, to identify any unsafe features or potential hazards and to provide recommendations for rectifying them during all stages, from planning to early operation (PIARC, 2011; ETSC, 1997; NRA, 2012).” (
  • A road safety inspection (RSI) is a systematic, on-site review of an existing road with the aim of identifying hazardous conditions, faults and deficiencies that may lead to serious crash outcomes.” (

The iRAP results should be used in conjunction with other road safety techniques.  iRAP recommend that all road improvement schemes that lead to a significant change in the highway features are, as a minimum, subject to Road Safety Audit during design and before being opened to the public. Road Safety Audits and RAP projects are not mutually exclusive, they can and should be used together to identify road user risk and to improve the safety of road designs.  Both methods can and are being used in conjunction to successfully improve safe road design.  

The inclusion of the Star Rating of a Design as part of the Road Safety Auditors assessment of a road design is encouraged and Auditors can be accredited to undertake these vital objective measures of safety performance worldwide – see for further details.

All the iRAP road survey data which is gathered around the world, is processed through ViDA, our central data base.