Zheng, P. and McDonald, M.
Evaluation of the effects of ramp metering on merging operations.
Transportation Research Record, 2012, . (doi:10.3141/2012-12).
Merging on motorways represents one of the most difficult and dynamic
maneuvers of all driving subtasks. Merging operations at uncontrolled
ramp junctions have been extensively investigated. With the rapid implementation
of ramp metering techniques, many junctions are now operated
under ramp metering control. Little research has been done to
investigate the possible effects of ramp metering on the merging operation.
The research described in this paper focuses on the comparisons of
merging operations under both metered and unmetered scenarios. Time
series data of the merging process were collected with the Transportation
Research Group instrumented vehicle and video cameras at a tapered
motorway merge site. The data included accurate vehicle speed measured
by laser speedometer, leading and following headway measured
by radar, and driver’s eye movement derived from an in-car camera.
Following a comprehensive analysis of the data, it was found that merging
operations under ramp control could be significantly different from
free merging. Merging maneuvers may become more difficult as a result
of ramp control. The equity implications of such effects are discussed. It
is believed that the understanding gained from this research will be
useful for the design and operation of ramp metering.
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