Saturday, November 17, 2018

Pedestrian & Bike Underpass of Alaska Highway?

Crossing of the Alaska Highway by bike or foot is a challenge.  There are no designated crossing points of the highway between the lights at 2-Mile Hill to the north and the lights 6 km to the south at Robert Service Way.  Yet we have a major multi-use path between downtown and the neighborhoods west of the Highway at the north end of the airport there are no safe crossing points.  Not only for cyclists, but there is considerable pedestrian travel from McIntyre and Hillcrest, walking downtown around the north end of the Airport.
Excerpt from Whitehorse current Cycle Commuting Map.

So in the age of extravagant spending on highways, why not providing a safe, separated crossing of the Alaska Highway?  This would not only benefit cyclists, but also all the walkers; by separating the crossing it would not inconvenience drivers either.  Although this may seem a bit of a radical idea for 1950's-era Whitehorse, in progressive sustainable transportation countries it is the common way of keeping vulnerable road uses safe when crossing major roads: they recognize that the two modes are not compatible and need separated spaces.

Cycleway underpass in Oulu, Finland.  Note large comfortable size that accommodates snow clearing equipment (
I would propose the underpass be located at the north end of the airport.  This location would service both Hillcrest and folks coming down from McIntyre.  Also if the trail on the west side were extended to Valleyview folks could use the underpass to access downtown via the airport/Black Street gully stairs.   It is already grade-separated on the east-side so only only the west side would need to have a ramp down from the trail.  Here is what it could look like:

Proposed location for Alaska Highway underpass at north end of Airport.
I did some calculations:  A 3.6 m high underpass can be accommodated under the highway here.  (3.6 m is a recommended height I found in a reference that can accommodate snow clearing equipment).  It should be a big, open, lighted box underpass that is lit and inviting, not a dank culvert such as used on Hamilton Blvd (look to the dutch examples to see how to do these right).   The path would slope up from the airport trail at 3% grade through the underpass.  Then on the west side the trail would need to gain another 2.5 to 3 m to reach the elevation of the ditch on the west side.  This would be a ramp down of about 55 m long at 5% (which is the recommended maximum grade for All Ages and Abilities (AAA) cycleways).  It would be tight on the west side so some retaining walls would likely be required at the underpass entrance, but these are used in many places around Whitehorse (Pelly Construction's yard on Industrial Road, Robert Service Way/Millennium Trail, etc.) So it is all do-able.

If we are willing to spend millions on the Alaska Highway, why shouldn't we expect some safe, separated infrastructure for vulnerable road users too?


Doug Hitch said...

Excellent idea. Bravo. It would increase foot and cycle traffic. Oh and maybe save a few lives too.

Unknown said...

I think the idea has its merits.