Speed changes in rural single-lane roundabouts converted for road trains Charlotte Tønning M.Sc. in Eng Aalborg University Niels Agerholm Associate Professor Aalborg University Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 1 of 26
Agenda Background Safety and speed Method Data Results Summary Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 2 of 26
Background Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 3 of 26
Denmark and road trains It came late to Denmark Trail in 2008 Prolonged several times. Now to 2030 Highly requested from Danish Transport and Logistics industry Swedish and Finnish schedule as role model Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 4 of 26
Where? ~ 4,000 km Mainly state roads Motorways Other state roads Selected industrial areas Considerable harbours Transport centres Expected all build in 2016 2014 2016 Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 5 of 26
Why road trains? Up to three time more freight/vehicle Save money due to less drivers Environmental protection? Safety effects? Heavily requested Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 6 of 26
Outcome based on national reporting Direct effects: Rebuild road network (Million 17) Additional operational costs (Million 0.2) No measurable extra attrition Saved cost/km 0.45 Reduced CO2 emission Immeasurable effect on noise Indirect effects: No. of recorded accidents has gone down (all and truck-related) Accident frequency from 0.34 (2007) to 0.29 (2010) No. of recorded accidents with road trains: 4, expected: 16 Other road users feel insecure Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 7 of 26
Speed and risk Higher speed = higher risk Higher speed = more serious Higher kinetic energy = more damages Power Model Risk Fatal Accidents Serious ínjuried Slightly ínjuried Damage only Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 8 of 26
Problem statement How is the speed of cars affected in roundabouts rebuilt for road trains? Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 9 of 26
Methods I Literature review Analysis approach and method: Before/after study With/without study Traffic counts Speed-registration and -analyses All based on camera registrations Legend Line for center axis Outside wheel Area reserve, 30cm Coachwork Area reserve, 30cm Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 10 of 26
Methods II Traffic counts Speed registrations Camera registrations Calibration with T-calibration Calibration with T-analyst Auto detection of speeds with RUBA software Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 11 of 26
Methods III Traffic counts Speed registrations Camera registrations Calibration with T-calibration Calibration with T-analyst Auto detection of speeds with RUBA software Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 12 of 26
Methods IV Traffic counts Speed registrations Camera registrations Calibration with T-calibration Calibration with T-analyst Auto detection of speeds with RUBA software Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 13 of 26
Data Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 14 of 26
Data collection Three selected locations (roundabouts) A part of the road train road network Single-lane rural roundabouts Roughly identical geometrical design Roughly identical AADT and type Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 15 of 26
Selected locations North Denmark AADT 4-7.000 Rural areas Considerable heavy traffic 2 1 3 Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 16 of 26
Selected trips Only cars Only under free-flow conditions Random distributed trips (weekday and time) For each registration period: 10 hours with 10 trips 4 *100 trips in total 2 1 3 Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 17 of 26
Design changes In one selected roundabout (before/after) (1) Reduced central island Added a low profile mountable apron Two other roundabouts: With a low profile mountable apron (2) Without a low profile mountable apron (3) 1 1 2 3 Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 18 of 26
Results Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 19 of 26
Traffic counts Cars Counted hours Cars/hour Location 1 (before) 36,736 119 309 Location 1 (after) 41,798 136 307 Location 2 (with) 13,632 40 341 Location 3 (without) 24,308 126 193 Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 20 of 26
Speed analyses Location 1 (before) Location 1 (after) Location 2 (with) Location 3 (without) Overall mean speed 27.9 km/h 35.7 km/h 32.8 km/h 32.0 km/h Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 21 of 26
Statistical tests Statistically significantly difference Roundabout Mean speed Before After With 1 Before 27.9km/h 1 After 35.7km/h <0.05 2 With 32.8km/h <0.05 <0.05 3 Without 32.0km/h <0.05 <0.05 0.59 Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 22 of 26
Speed distribution 16 Location 1 14 12 Studied cars 10 8 6 4 Før Before Efter After 2 0 192123252729313335373941434547495153555759 Speed km/h Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 23 of 26
Results Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 24 of 26
Summary Effect from establishing a low profile mountable apron: The speed increases up to 8 km/h More speed variation All things being equal: an increased accident risk Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 25 of 26
ThankYou Charlotte Tønning Traffic Research Group Aalborg University cht@civil.aau.dk Niels Agerholm Traffic Research Group Aalborg University +45 61 78 04 55 na@civil.aau.dk Niels Agerholm Charlotte Tønning Division of Transportation Engineering Aalborg University No. 26 of 26