Istrazivanja i projektovanja za privreduJournal of Applied Engineering Science


DOI: 10.5937/jaes0-29180 
This is an open access article distributed under the CC BY 4.0
Creative Commons License

Volume 19 article 861 pages: 853-861

Tri Tjahjono*
Universitas Indonesia, Faculty of Engineering, Department of Civil and Environmental Engineering, Kota Depok, Indonesia

Martha Leni Siregar
Universitas Indonesia, Faculty of Engineering, Department of Civil and Environmental Engineering, Kota Depok, Indonesia

Universitas Indonesia, Faculty of Engineering, Department of Civil and Environmental Engineering, Kota Depok, Indonesia

The aim of this study is to develop the power model of the relationship between speed and traffic safety. As the inter-urban roads are characterised with heterogeneous traffic, the heterogeneity became the focus of the analysis. The present study analysed the effects of various types of vehicles through a number of speed change combinations and developed six equations: number of fatal accidents, number of fatalities, number of fatal and serious injury accidents, number of fatal or serious injuries, number of injury accidents and number of injured road users. The results indicated that the Power Model showed high predictability of the speed-accident relationship. The models fit the data well with Rsq in the range of 0.6-0.8. The vehicle category-specific ratio power models exhibited how traffic heterogeneity accounts for traffic safety. The equations' power varies with the types of vehicles, indicating the different sensitivity of accidents and casualties to the speed ratios. Overall, with the power estimates around one, except for all injured victims, the estimates were systematically smaller than those that were initially inferred in Nilsson's Power model. The values indicated that the increase in speed determined the increase in the number of accidents and casualties from year to year. The present study successfully developed the first speed-traffic safety Power Model for Indonesia. As it is exclusively dependent on the speed changes, the model can well describe the direction of change in traffic safety irrespective of other changes in the driving environment factors.

View article

This research was funded by TADOK Grant Universitas Indonesia 2019 No. NKB-0167/UN2.R3.1/HKP.05.00/2019 The Authors would also like to thank the Project Management Unit of the Australian-funded “EINRIP Monitoring & Evaluation Programme, Fifth Monitoring Survey, Final Report 2017” for the permission to use the data.

1. Aarts, L. and van Schagen, I.(2006). Driving speed and the risk of road crashes: A review. Accident Analysis & Prevention, vol. 38, no. 2, p. 215–224. DOI: 10.1016/J.AAP.2005.07.004.

2. Gargoum, S. A. and El-Basyouny, K.(2016). Exploring the association between speed and safety: A path analysis approach. Accident Analysis and Prevention, vol. 93. DOI: 10.1016/J.AAP.2016.04.029.

3. Nilsson, G.(2004). Traffic Safety Dimensions and the Power Model to Describe. Bulletin 221. Lund Institue of Technology, Department of Technology and Society, Traffic Engineering, Lund.

4. Elvik, R., Christensen, P. and Amundsen, A.(2004). Speed and road accidents. Report Number 740/2004, Institute of Transport Economics, Norwegian Centre for Transport Research. ISBN: 82-480-0451-1

5. Elvik, R.(2013). A re-parameterisation of the Power Model of the relationship between the speed of traffic and the number of accidents and accident victims. Accident Analysis and Prevention, vol. 50, p. 854–860. DOI: 10.1016/J.AAP.2012.07.012.

6. Elvik, R. et al.(2019). Updated estimates of the relationship between speed and road safety at the aggregate and individual levels. Accident Analysis and Prevention, vol. 123, no. November 2018, p. 114–122. DOI: 10.1016/J.AAP.2018.11.014.

7. Tanishita, M. and Wee, B. Van.(2017). Impact of vehicle speeds and changes in mean speeds on per vehicle-kilometer traffic accident rates in Japan. IATSSR, p. 0–5. DOI: 10.1016/J.IATSSR.2016.09.003.

8. Wang, X. et al.(2018). Speed, speed variation and crash relationships for urban arterials. Accident Analysis and Prevention, vol. 113, no. November 2016, p. 236–243. DOI: 10.1016/J.AAP.2018.01.032.

9. Roy, R., Saha, P. and Kumar, A.(2017). Speed Distributional Trends on Two-lane Roads with Mixed Traffic under Heavy Flow. Procedia Engineering, vol. 187, p. 465–470. DOI: 10.1016/J.PROENG.2017.04.401.

10. Quddus, M.(2013). Exploring the Relationship Between Average Speed, Speed Variation, and Accident Rates Using Spatial Statistical Models and GIS. Journal of Transportation Safety and Security, vol. 5, no. 1, p. 27–45. DOI: 10.1080/19439962.2012.705232.

11. Siregar, M. L., Tjahjono, T. and Nahry.(2020). Endogenous Relationship of Accident Occurrence with Speed, Traffic Heterogeneity and Driving Environment on Inter-Urban Roads in Indonesia. Journal of Applied Engineering Science. doi: DOI: 10.5937/JAES0-25837.

12. Australia-Indonesia Partnership.(2017). EINRIP Monitoring & Evaluation Programme, Fifth Monitoring Survey, Final Report.

13. IRSMS Login. Available at: (Accessed: 23 March 2019).

14. Soehodho, S.(2017). Public transportation development and traffic accident prevention in Indonesia. IATSS Research, vol. 40, no. 2, p. 76–80. DOI: HTTPS://DOI.ORG/10.1016/J.IATSSR.2016.05.001.

15. Tjahjono, T.(2016). Identification of motorcycle crashes and possible roadside protection on rural low-volume roads in Indonesia. Transportation Research Circular. Transportation Research Board. Available at:

16. Mountain, L. J., Hirst, W. M. and Maher, M. J.(2005). Are speed enforcement cameras more effective than other speed management measures? The impact of speed management schemes on 30 mph roads. Accident Analysis & Prevention, vol. 37, p. 742–754.

17. Kloeden, C., Woolley, J. and McLean, J.(2007). A Follow-up Evaluation of the 50km/h Default Urban Speed Limit in South Australia. in Proceedings of Australasian Road Safety Research, Policing and Education Conference. DOI: HTTPS://DOI.ORG/10.1016/J.AAP.2018.11.014.

18. Islam, M. T. and El-Basyouny, K.(2015). Full Bayesian evaluation of the safety effects of reducing the posted speed limit in urban residential area. Accident Analysis & Prevention, vol. 80, p. 18–25. DOI: HTTPS://DOI.ORG/10.1016/J.AAP.2015.02.026.