Bilister og Modulvogntog

Abstract

I dette kandidatspeciale er det undersøgt, om udbygninger af rundkørsler til kørsel med modulvogntog er med til at øge hastigheden for personbiler igennem rundkørslen. Ombygning af rundkørslerne til kørsel med modulvogntog er ofte gjort ved at gøre midterøen mindre i diameter og derefter etablere et over-kørselsareal. Dette overkørselsareal er i nogle rundkørsler overkørbart, og det er disse rund-kørsler, der er i fokus i dette speciale. Problem-stillingen er undersøgt ved en før- og efteranalyse, samt en med- og udenanalyse på i alt tre projektlokaliteter. Indsamlingen af data er foretaget ved hjælp af videoanalyse. Databehandlingen er foretaget ved hjælp af to computerprogrammer, T-analyst og RUBA, hvor hovedandelen af efterbehandlingen er foretaget i RUBA, og resultaterne fra T-analyst har fungeret, som en referenceanalyse, så det har været muligt, at afgøre om hastighederne, beregnet ved hjælp af RUBA, er valide. I efterbehandlingen er der ligeledes anvendt statistiske analyser for, at afgøre om, der er en signifikant forskel i hastighederne mellem de udvalgte rundkørsler. Opsummeres resultater-ne kort, viste hastighedsanalysen, at den mak-simale forskel i gennemsnitshastigheden er på 9 km/t, hvilket er mellem før- og efteranalysen, hvor gennemsnitshastighederne er henholdsvis 28 km/t og 37 km/t. De statistiske analyser viste, at forskellen mellem hastighederne i rundkørsler med og uden overkørbart overkørselsareal er signifikant forskellige, og det kan derved konkluderes, at ombygninger af rundkørsel med overkørbart overkørselsareal giver øgede hastigheder for personbiler.

In many years road trains has been used internationally, but in 2008 were the first trials with road trains initiated on selected parts of the Danish national road network. The period of the trial was at first nominated to three years, but was extended several times. The trial period is now prolonged to 2030, which in reality makes it a permanent arrangement. In the initial stages towards the trial period the transport industry expressed their needs for road trains, which led to the ongoing trial. Road trains in Denmark are up to 25,25 m long, and therefore it has been necessary to rebuild state roads and selected municipal roads, were these road trains are allowed, to ensure suffi-cient space. The rebuilding is mainly required in the nodes, which involve design chances of the nodes. Around 150 locations are in total rebuild so far, where a considerable part are rounda-bouts, to ensure sufficient space for the road trains. This project focus on single-lane rounda-bouts, where the central island is reduced, and the reduced area is added to the lane. The re-building of the single-lane roundabout makes the turning radius bigger, because of the increas-ing width of the lane, which could allow especially private cars to increase their speed through the roundabout. The hypothesis is therefore, that the rebuilding of the single lane roundabouts will increase the speed noticeably through the roundabouts. An increase in the speed could led to an increase in the accident risk and an additionally increase in speed variation, which is a normally outcome of an increasing speed level. To confirm the hypothesis is two studies made: A before and after study in the same rounda-bout and a with and without study in two almost identical roundabouts. The three roundabouts are all outside urban areas, have an AADT of 4.000 to 8.000, and the roads leading up to the roundabout have a 80 km/h speed limit. For each of the three roundabout approximately one week of video registration were recorded. The study only focus on private cars driving under free flow conditions, and the study is based on 100 cars per week per location, so 400 cars in total for the study. The speed through the roundabouts are measured from two timestamps between two appointed location in the roundabout. The result of the study were, that the speed in the before and after study are almost 28 km/h and 37 km/h respectively, and the speed in the with and without study are almost 32 km/h and 33 km/t respectively. The results of the study are tested for the same mean value using statistical analysis. The combinations that were tested for same mean value are before and after, with and without, before and with, before and without, after and with, after and without, and finally before/with and after/without. The result of the statistical analysis are, that none of the combination except the with and without have same mean value, which shows, that the speed has increase since the rebuild of the roundabouts. An increase in the speed in rebuild roundabouts might reduce the traffic safety and increase the risk of accidents, according to the power model.

A master thesis from Aalborg University

Bilister og Modulvogntog

[Private Cars and Road trains]