Point-to-point speed enforcement systems: Speed limits design criteria and analysis of drivers’ compliance Alfonso Montella ⇑ , Vincenzo Punzo, Salvatore Chiaradonna, Filomena Mauriello, Marcello Montanino Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, 80125 Naples, Italy article info Article history: Received 13 August 2014 Received in revised form 27 January 2015 Accepted 27 January 2015 Keywords: Speed limits Section speed enforcement Average travel speed Inferred design speed Operating speed Speeding Highway safety abstract Point-to-point (P2P) speed enforcement is a relatively new approach to traffic law enforce- ment. Its technology allows vehicles whose average speed exceeds the speed limit over the controlled section to be fined. It therefore encourages compliance over distances longer than those where spot enforcement policies have been in place. In this paper, a procedure for consistently setting speed limits with such enforcement systems is proposed. Such a method has been applied to design the speed limits on two motorways in the district of Naples, Italy, where P2P enforcement systems became opera- tional in 2009 and 2010. The speed limits, which were set using the Italian geometric design standard to assess vehicle stability and stopping sight distance, have been compared with those provided by using well-known international standards. The impact of the newly designed speed limits and of the P2P enforcement system on drivers’ speeding behaviour has been quantified for each highway section and vehicle type. In fact, accurate measurements of the average travel speeds of each vehicle crossing the enforced sections, before and after the activation of the system, were available. The migra- tion from the old speed limits with spot speed enforcement to the new approach resulted in a notable increase in drivers’ compliance to the speed limits with a remarkable decrease in both the average of individual speeds and in their standard deviation. In addition, the analysis of 3 years of data shows that a gradual adaptation of drivers’ behaviour to the system took place. In particular, a decreasing compliance to the speed limits points to a non-optimal system management. Finally, the results of a revealed pref- erence survey allowed us to make a behavioural interpretation regarding the significantly different impacts measured on the two motorways. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction Travelling at too high speed for the road environment is considered to be a major factor contributing to road crashes (Aarts and van Schagen, 2006; Hauer, 2009; Montella and Imbriani, 2015; Montella et al., 2010, 2011, 2015; Neuman et al., 2009; OECD, 2006; Yannis et al., 2013). Speeding is not simply driving faster than the speed limit; it is also driving within the speed limits but too fast for the prevailing weather, light, traffic and road conditions (Montella et al., 2013; NHTSA, 2012). http://dx.doi.org/10.1016/j.trc.2015.01.025 0968-090X/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +39 081 7683941; fax: +39 081 7683946. E-mail addresses: alfonso.montella@unina.it (A. Montella), vinpunzo@unina.it (V. Punzo), salvatorechiaradonna@alice.it (S. Chiaradonna), filomena. mauriello@unina.it (F. Mauriello), m_montanino@msn.com (M. Montanino). Transportation Research Part C 53 (2015) 1–18 Contents lists available at ScienceDirect Transportation Research Part C journal homepage: www.elsevier.com/locate/trc