Naish D.A.,13 Adelaide Street
Road and Transport Research | Year: 2015
An investigation into various road safety barrier run-out length methods and the estimated cost differences due to resulting 'length of need' differences is presented. The study establishes an automatic calculation method for a large number of geometric scenarios and achieves this by developing regression algorithms for clear zone, shy line offset and run-out length. The algorithms are implemented into computer code to calculate 'length of need' for road safety barrier for straight roads and roads with horizontal curves from 100 m to 1000 m radius. Clear zones are calculated with variable fill slopes and also include a clear zone adjustment factor on the outside of horizontal curves. Hazards are located at various distances from the edge line for curved roads, and at the outer edge of the calculated clear zone for straight roads. Barrier offsets are set to 1 m for all roads, and also at the calculated shy line offset for straight roads. In total, 11 605 geometric scenarios and the differences in 'length of need' due to different recommended run-out lengths are calculated. Cost differences are estimated assuming a base cost of installing standard w-beam road safety barrier. Overall it is estimated that reducing recommended runout lengths could reduce costs by approximately A$4000 for one-way road installations.
Faulkner L.,13 Adelaide Street |
Dekker F.,13 Adelaide Street |
Gyles D.,13 Adelaide Street |
Papamichail L.,Technical University of Crete |
Papageorgiou M.,Technical University of Crete
Transportation Research Record | Year: 2014
The recently developed traffic-responsive feedback control strategy HERO (heuristic ramp metering coordination), which coordinates local ramp-metering actions in freeway networks, was implemented on the M1 and M3 freeways in Queensland, Australia. HERO employs an extended version of the feedback regulator A LINEA at the local level; it outperforms uncoordinated local ramp metering and approaches the efficiency of sophisticated optimal control schemes. HERO has been implemented by the Department of Transport and Main Roads of the State of Queensland at six on-ramps of the Ml and M3 freeways. The results show significant improvements in traffic throughput and travel times compared with the previously used fixed-rate ramp-metering system. A rapid economic benefit analysis determined a benefit-cost ratio of 13.8: 1 at a 7% discount rate and, therefore, an extremely strong economic merit for the implementation of HERO. The economic payback period for the capital expenditure 011 Ibis pilot is approximately 4 months.