Study on The Safety Length of Acceleration and Deceleration Lane of Left-Side Ramp on Freeway

Jin Zhou
Jing Fang
Rong-gui Zhou

Acceleration and deceleration lanes are the critical parts which ensure safety maneuver between main lane and ramp. Due to terrain constraints, the left exit or left entry ramp used in the interchange design doesn’t accord with the right-hand driving habits and drivers’ expectations. To ensure the safety and efficiency of the operation, it’s necessary to study the safety length of the acceleration and deceleration lanes on left-side ramp considering the vehicles’ operating characteristic of merging or diverging. According to the headway distribution of main lane in merging area, the probability model of vehicles in the acceleration lane merged into the main lane was established based on the acceptance gap theory. The length of the acceleration lane can be calculated under the different operating speed and merging probabilities. Based on Secondary reduction theory, the required safety length of deceleration lane driving from the inner lane to the left-side exit ramp was determined to ensure that those diverging vehicles do not affect the operation of the vehicles on the main lanes. The recommended length of acceleration and deceleration lane will provide a technical sustain to the safety design of interchange.



The 6st Humanist Conference

The 6th HUMANIST Conference will take place 13-14 June 2018 in the Hague, The Netherlands. The scope of the conference covers a wide range of topics on Human Factors in Transport. Tania Willstrand and Alexander Eriksson will present their research results.



Enkät om trafiksäkerhet genomförs i 50 länder

At the Road Safety on Five Continents Conference, RS5C, one entire session presented a large survey of road users' attitudes in 38 countries. Results show large differences between countries in many areas, both regarding behavior and attitudes. A new survey...


Good results with alcohol interlock program according to Swedish study

An alcohol interlock program makes it possible for drink driving offenders to continue their everyday lives. In a Swedish study most of the participants were satisfied with the program and experienced improved health. They also reported drinking alcohol more...


Traffic safety in the spotlight

Today the Conference Road Safety on Five Continents (RS5C) opened in Jeju Island, South Korea. More than 220 participators have come from all over the world to present findings and learn about traffic safety. Dr. Young Tae Kim, Secretary-General of the...


VTI will develop simulators for ambulance staff

VTI has initiated a pilot study for paramedics with the Centre for Teaching & Research in Disaster Medicine and Traumatology and Linköping University. The aim is to give ambulance staff the opportunity to practice critical medical tasks in a moving vehicle in...


Unique electrified road opens in Sweden

The world’s first electrified road recharging the batteries of cars and trucks while driving opened in Sweden. The Swedish Minister for Infrastructure, Tomas Eneroth, was at the formal inauguration of the electrified road on April 11, 2018. VTI is one of 22...


Swedish road safety spreads internationally

Sweden is a leading country in terms of road safety, and the research conducted by the Swedish National Road and Transport Research Institute (VTI) has contributed to increased safety. VTI’s remit includes disseminating research results and keeping up to date...