A four step process to convert road traffic congestion to free flow

Submitted by john on Mon, 16/12/2019 - 16:26

1. Metering removes congestion-delay to buses, enables a green wave, and smoothing at minor crossings, so also remove delays to buses caused by traffic signals, and is of greater benefit to buses than a bus lane. Metering instead of a bus lane in Hoddle St, increases capacity by 20% and reduces delays to cars by 15 minutes. Metering can be applied to Punt Rd, removing congestion, permitting a green wave and giving priority to buses. Congestion anywhere should never be permitted to occur, on the basis that the time it wastes is more costly than the alternatives. Congestion can only be removed by metering.

2. Pedestrian crossings should be staged and minor streets converted to Restricted Crossing, U-turn to smooth traffic flow in the counter-peak direction, reducing the number of stops and the CO2 emissions.

3. Conventional intersections are relatively dangerous, with twice the crash rate of 2-phase intersections. Installing 2-phase intersections on a four-lane road gives it the capacity of a six-lane road, so is cheaper accordingly. Intersections can be upgraded to 2-phase within the existing footprint. They can have half the cycle time and half the delay. Right turn crossovers are preferable because they are more driver friendly, and the extra signal hardware is justified. 2-phase intersections reduce the delay at the metering queue and the toll needed for queue-jumping. The 2-phase DDI has: half the delay; twice the capacity; half the crashes; and fewer gridlocks, compared to a single point interchange.

4. To get the full benefit of a green wave, as many people as possible should jump the metering queue. If 90% of people are permitted to jump a metering queue for a small toll, most trips can be in a green wave, at the speed limit, with minimum braking, acceleration, time wasted, and half the CO2 emissions. A free access queue is also required so that demand is managed by queue delay. It is much more refined in application than just pricing.

A suitable policy might be to have a traffic operations team, charged with trialling replacement of all congestion with metered lengths and green waves, enhanced in steps by smoothing minor crossings, two-phase intersections, and tolled queue-jumping. They should be charged with publishing the strategy for each route, with provision for the public to protest each step, including the original metering, and force a cessation of the step, after its trial, and a survey of users to reinstate or reject the step. We might start with Hoddle St-Punt Rd and follow up with Alexandra Pde-Elliott Ave. A green wave is particularly relevant during any construction phase.

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