Below-grade traffic circles
Most, if not all, of the concerns voiced by
delegations at the Jan. 14, 2008 special meeting of Guelph City Council, can be
adequately addressed by having MTO adopt an interchange design not considered by
either Stantec or MTO.
We don't need PARCLO's or diamond interchanges at all.
First of all because of the horrendous cost, secondly because of the need to
expropriate houses and land, and thirdly because of the long construction
interval involved. And on top of that are the environmental issues.
The perfect solution is traffic circles, but not surface ones that MTO
considered and rejected.
The answer for the Hanlon is below-grade traffic circles.
They can be constructed at Kortright, Stone and College for a fraction of the
$50 million estimate for the current plan.
Below-grade traffic circles with ascending and descending ramps to/from the
Hanlon allow for complete vehicle movement in all four directions, and in
addition permit a vehicle that has missed its desired exit, to use one of the
circles and reverse direction.
As currently planned, Kortright/Downey and College will pass under the Hanlon.
Rather than building straight thru tunnels at these locations, plans could
easily be modified to build circular tunnels, ie. below-grade traffic circles
instead. While the cost would be higher, money can be saved overall by deploying
the same design at Stone Rd., and eliminating the monster overpass/interchange
presently planned for that location.
With below-grade traffic circles, few, if any, houses and property need be
expropriated.
With a shorter construction period, greenhouse gases from the machinery can be
reduced.
The solution for safety of pedestrians, is to build overhead walkways over the
Hanlon at each intersection. Each should be constructed with side barriers to
prevent rock throwing onto vehicles passing below.
MTO's objection to this type of design, is likely to be, that there is
insufficient distance between College and Stone, and Stone and Kortright/Downey
to construct 'on' and 'off' ramps that are safe. With approximately 1 km between
each of these main arteries, there should be ample space for ramps. The ramps
can be straight, from the traffic circle to the Hanlon, allowing for faster
acceleration to permit merging with Hanlon traffic. 'On' ramps from PARCLO's,
being curved, do not allow for rapid acceleration until the vehicle reches the
straight section just prior to entering the highway.
Below-grade traffic circles are the perfect solution to solve the Hanlon' s
problems.
Click for a sketch.
For more info on traffic circles go to
www.roundabouts.ca
Barry Wrigglesworth