The impact of route familiarity on drivers' speeds, trajectories and risk perception

Differences in driving behavior due to the presence of users familiar/unfamiliar with the road are commonly considered in both road design (guidelines for road design) and traffic engineering (calculation of the equivalent traffic flow). However, although considered, the matter is largely unexplored: there is a lack of theoretical foundations and data on determining the impact of route familiarity on accident rates, speed choice and risk perception. On the other hand, some literature studies confirm that route familiarity is influential on driver behavior, mainly increasing inattention while driving, encouraging research in this sense. This paper reports the results of an on-road test carried out on a two lane rural road in the District of Bari in Puglia Region (Italy) over six days of testing, in order to find relationships between route familiarity, speed and trajectories selection, and risk perception. The particular schedule used for the tests allows to consider the influence of familiarity on the behavior of the test drivers. In particular, data were analyzed by considering the influence of road geometry and human factors. Speed choice seems to be affected by route familiarity: speed increases with the repetition of travels on the same route if the tests are scheduled in consecutive days. The speed increasing tendency is different according to the risk inclination of the different drivers and according to the different road geometric characteristics. The process of trajectory selection at curves is also influenced by route familiarity: the radius of curvature of the trajectories selected at curves increase with the repetition of travels on the same route, showing curve-cutting and encroachments. The radius increasing tendency is different according to the different geometric features of the curve sections. Furthermore, the particular experimental design (4 test repetitions in different speed driving conditions for each day of testing) allowed to consider also changes in risk perception over time based on speed measurements. As for what concerns the speed selection process, the comparison between the different speed driving conditions (free speed choice, driving at low speed, driving at medium speed, driving at high speed) showed some noticeable tendencies. On combining these results, the on-road test showed that route familiarity is clearly influential on the driving process. Since the experiment was carried out on a very low-volume road, some considerations about the practical impact of this phenomenon on the road design and safety-based maintenance are given. In fact, both speeding and curve-cutting tendencies related to route familiarity, are important safety issues to address, also considering that familiar users are more prone to inattentive driving.


  • English

Media Info

  • Pagination: 12p
  • Monograph Title: Proceedings from the 17th International Conference Road Safety on Five Continents (RS5C), Rio de Janeiro, Brazil, 17-19 May 2016

Subject/Index Terms

Filing Info

  • Accession Number: 01625760
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Files: ITRD, VTI
  • Created Date: Feb 9 2017 12:07PM