Glenorchy City Council announced last week (September 2) that it would reduce speed limits from 50kph to 40kph in some streets in the Glenorchy CBD.

According to the Council’s announcement of their decision, the primary purpose is to “increase safety for motorists and pedestrians as well as contributing to a calmer and slower environment where shoppers can relax and enjoy spending time in Glenorchy“.

But Council’s focus on speed limits bears closer examination.

If the intended aim is to slow traffic, changing speed limits appears to be a cheap option; simply install some signs. But without enforcement (which does cost), they will have little effect.

Council should have given greater consideration to traffic calming measures such as wombat crossings (we already have one in Terry Street). Council has already made a start with some traffic islands in the centre of Main Road, and planned ramps around the section outside Northgate. Traffic calming infrastructure will calm traffic 24/7, with no change to speed limits and no need for enforcement.

If the intended aim is to improve safety, Council could have made Main Road outside Northgate one-way, or even closed it off altogether. Historically, business has always claimed that removing parking outside their business will be bad for their business but most evidence refutes those claims. Read these reports from Sweden and Brisbane (Australia).

We don’t know how fast traffic travels now. Council has published no statistics. While the current speed limit is 50kph, it is very likely that little current traffic exceeds 40kph. Traffic volumes during the day already make 50kph difficult to achieve. And drivers in a CBD street are generally so focused on other traffic, finding parking spaces, noticing changes in traffic lights, and anticipating movements by pedestrians, that a speed limit sign on the roadside will not be noticed.

I did learn from the map in the Council’s announcement that there are already a couple of streets in the CBD with 40kph speed limits (note the blue streets on the map). I doubt any driver noticed. I’ve driven those streets hundreds of times over the years and I certainly didn’t. But then again, I suspect I didn’t break the speed limit.

Interested readers may wish to view a discussion by the Infrastructure Committee (starts at 27:45) of the Hobart City Council on June 24 (2020) about a proposal to reduce speed limits in Hobart. After stating the universally accepted assertion that higher speeds result in more serious accidents, he became considerably more vague repeatedly indicating that “road engineers” would know what speed would be appropriate for each street. In essence, he asserted that the slower the speed, the less serious the accident. No science!

There is a great deal of evidence that we can’t regulate our way to safety. We must design our streets to be safe. Here is just one short article illustrating that proposition.

In summary, while the speed limit changes will probably have no effect on traffic speeds, the announcement of the changes will certainly create a perception amongst the public of increased safety. And if that is the primary purpose, well and good. But let’s not kid ourselves, the changes are symbolic.

References

“The impact of lowered speed limits in urban areas”, Monash University Accident Research Centre, 2008.