Development of a micro-simulation model for motorway roadworks with the use of narrow lanes and lane closure schemes

This study presents a newly developed micro-simulation model for motorway roadwork sections to evaluate the efficiency of different temporary traffic management schemes (TTMSs) such as the use of narrow lanes, offside and inside lane closures. The effect on traffic performance (i.e. capacity and delay) of various parameters (e.g. flow rates, percentage of heavy goods vehicles, roadwork zone lengths and speed limits) has been tested. The reason for building this model from scratch is the inability of an industry standard software package (i.e. S-Paramics), which has been made available for this research, in appropriately presenting traffic behaviour at motorway roadwork sections. The newly developed micro-simulation model was built using the FORTRAN programming language. It was developed based on car-following, lane changing, gap acceptance, lane closure and narrow lanes rules.Data from four sources (taken from different sets of data from UK motorways sites) were collected and analysed. The data was used in developing, calibrating and validating the model. Observations from motorway roadwork sites with narrow lanes scheme show certain prominent drivers’ behaviours, namely avoiding passing HGVs on adjacent lanes and lane repositioning before passing an HGV. The simulation results revealed that, under low traffic demand, the use of narrow lanes scheme seems to perform better in terms of capacity and delay than both offside and inside lane closure schemes, whereas under high traffic demand associated with high HGVs percentage (i.e. ≥ 25%), the use of offside lane closure scheme seems to perform better in terms of capacity and delay than narrow lanes scheme and inside lane closure scheme. The simulation results showed that the presence of HGVs has a large impact on reducing site capacity. The model also suggests that a stricter speed limit compliance should be imposed on motorway roadwork sections with the use of narrow lanes TTMS in order to maintain higher section capacity and reduced delays. Regression analysis was carried out based on the simulation results in order to provide equations for use in estimating section capacity and delay

Development of a microsimulation model for motorway roadworks with narrow lanes

This paper presents a newly developed microsimulation model for motorway roadwork sections to evaluate the efficiency of different temporary traffic management schemes (TTMSs) such as the use of narrow lanes, offside and inside lane closures. The effect on traffic performance of various parameters (e.g. flow rates, percentage of heavy goods vehicles (HGVs), roadwork zone lengths and speed limits) has been tested. The model was built using the FORTRAN programing language. It was developed based on car-following, discretionary lane changing, mandatory lane changing, gap acceptance and narrow lanes rules. Data from four sources (including data taken from different UK motorway sites) were collected and analyzed. The data were used in the verification, calibration and validation processes of the model. Observations from motorway roadwork sites with the narrow lanes scheme show certain prominent drivers' behaviors, namely avoiding passing HGVs traveling on adjacent lanes and lane repositioning before passing a HGV. Such behaviors were included in the modeling process which suggested that the presence of HGVs had a noticeable impact on reducing section capacity

Narrow lanes and their effect on drivers’ behaviour at motorway roadworks

In recent years, more use of narrow lanes as a temporary traffic management scheme (TTMS) on UK motorway roadwork sections has been made. The rationale is to free up carriageway space, especially for sites with high traffic demands needing repairs. What remains to be determined is the impact of this work on traffic operation. This is important due to the need to manage traffic operational turbulence which could affect the capacity as well as safety levels in roadwork sections. Site observations (mainly using camcorders from overhead bridges) were made which uncovered two discernible patterns of driving behaviour where narrow lanes are implemented at roadworks, especially when heavy goods vehicles (HGVs) are present: (i) “avoiding” passing/overtaking HGVs travelling in the adjacent lanes and (ii) lane “repositioning” while passing/overtaking which might cause some turbulence to traffic operation. From one site, almost half of the passenger car drivers (including small vans) who were following a HGV on the adjacent lanes were avoiding passing that HGV. Also, nearly three quarters of the observed passenger cars, the passenger car drivers tried to position their vehicles as far away as possible, laterally, from the adjacent HGV while passing/overtaking that HGV in order to widen the lateral gap between their vehicles and the HGV. This resulted in driving too close to the edge of the road markings of their current lane away from the HGV. Therefore, this paper aims to report on the “avoiding” and lane “repositioning” behaviours to help inform traffic management teams/designers using narrow lanes as TTMS and make them aware of such behaviours (especially for motorway sections carrying high percentages of HGVs). Also, the finding from these observations were used in the development of a new micro-simulation model in order to evaluate the effect of such turbulence