Mastodawn

I'm reading the "Keeping People Safe When Walking – Stream 2: Economic Assessment of Safer Speeds" report from Austroads.

"The findings of the CBA are clear. All 12 scenarios tested have a benefit-cost ratio (BCR) of more than one –
meaning the benefits for society outweigh the costs. Therefore, the key takeaway from this analysis is that
there appears to be a strong economic rationale for pedestrian focused speed limit reductions in a range of
urban settings."

https://austroads.gov.au/publications/road-safety/ap-r754-26

Keeping People Safe When Walking – Stream 2: Economic Assessment of Safer Speeds

This report aims to build evidence to support Austroads’ members in assessing speed limit reductions in lower speed, typically in urban contexts.

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Jesse Feb 24

"The results of the analysis may be conservative as they do not include benefits to cyclists, induced active
transport demand or modal and route shifts. This was due to a lack of data and evidence available to inform
the estimation of these second order benefits."

The report only includes economic benefits involving people walking.

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Jesse Feb 24

Skipping forward a bit to the numbers table.

The table shows a ratio between the cost to car travel times vs the benefits of crash reductions in the second column.
The third column shows the ratio of the cost to car travel times vs the benefits of crash reduction, the benefits of reconnecting pedestrians to facilities and services (Severance) and the benefits of having a nicer street(Amenity).

You can see that most of the benefit comes from pedestrian amenity and reduced severance. But in most of the scenarios there is a benefit simply from crash reduction.

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Jesse

On this very conservative report you can easily make the economic case for a default speed limit of 30km/h and for a maximum speed of 50km/h on inner city arterials (not pedestrian separated motorways) on crash costs alone.

The Amenity and reduced severance benefits are staggering. These are VC investment type numbers. Who wants to invest in a startup that switches 50km/h signs to 40km/h signs on roads adjacent to major trip generators for 6800% return?

Reduced severance benefits would be much larger for people on bicycles just due to the extra distance you can travel on a bicycle you are cut off from more possible services you could otherwise have had access to and that isn't included in these numbers

Something the report also pointed out which makes this report even more conservative in it's estimate of travel costs: "We note that there has been some recent debate around whether it is reasonable to value very small changes in travel time for motorists and freight (i.e. a one-minute increase in journey time on an average commute time of one hour) given these variations are likely within the ranges of typical variability in journey times making them relatively imperceptible. It could be argued on this basis that there is a
threshold below which travel time costs are irrelevant and should not be valued."