Looking at the ‘costs’ section, it seems to only consider costs to the government. But we should also consider costs to individuals of decreasing speed limits.
The largest of these is probably longer travel times; the entire purpose of roads is to travel from one place to another quickly! This is potentially a very large cost, and should be fairly tractable for you to estimate: look at the average length of time spent commuting, calculate how much longer journeys will take, and multiply by the average wage for motorists.
There are also other costs, in particular from the required increase in traffic stops. You note the cost of hiring more enforcement officers, but not the the stress of getting pulled over—most people are not used to getting arrested. Because officers typically have a lot of discretion in who they pull over, and what ticket they write, enforcement can be uncertain, arbitrary and unfair. Additionally, they can be dangerous: when approaching a car the policeman has none of the typical situational cues they use to evaluate a situation. They can’t see the person’s body language ahead of time, and weapons are easy to conceal. At some point they are probably going to ask the driver to reach into the glove compartment, which is a not uncommon place to store a firearm.
A couple of observations related to your points from Freetown, Sierra Leone (I’m not too sure if this would be similar to the locations considered here). First, there are lots of traffic jams. My journey times are _much_ more heavily dependent on the amount of traffic than speed limits. It’s pretty rare that there’s open, good-enough roads to get up speed (but when there are, drivers go pretty fast). Second, the police pull drivers over regularly—usually for no reason other than to check the driver’s license (as far as I can tell). It’s common that the police ask for money regardless of whether you have your license (e.g. it’s easy to say they saw you breaking some rule—the driver can’t do anything other than argue or pay up).
Hi, thanks for your comment and apologies for the somewhat belated response!
On increasing travel times—yeah I think this is a really interesting point and something that we didn’t consider when modeling the CEA. I think it may be best to discount the income effects of this intervention as a result of this. After a quick Google search, I have found some data on this from the UK—“Each 1 mph reduction in average traffic speed costs the UK economy in excess of £1Bn in lost productivity through extended journey times” (https://www.abd.org.uk/press-release-hes-proposed-motorway-speed-limit-reduction-to-60mph-borders-on-economic-vandalism/). This suggests the impact could be quite significant, though as the World Health Organization found that the economic impact of road traffic injuries is approximately 3% of GDP, I think the economic impacts would still be net-positive.
Clare’s point on traffic jams is an important consideration here, both for your point and for the promise of this intervention—if drivers are never getting up to the speed limit, then decreasing them looks less promising. This was a concern we were aware of, but we felt unable to address from our desktop research, but this is something we will highlight to the founders of this organization, and it is something that they will be able to assess when doing country scoping visits.
Perhaps these considerations make advocacy on seat-belt legislation look more promising than advocacy to reduce speed limits. This would be good to pass on to the potential founders so that they can weigh up these considerations.
On the stress of getting pulled over by the police, I am not sure I can comment usefully on this as I don’t know too much about it, but thanks for raising the concern, and thanks Clare for the insight from Sierra Leone.
Looking at the ‘costs’ section, it seems to only consider costs to the government. But we should also consider costs to individuals of decreasing speed limits.
The largest of these is probably longer travel times; the entire purpose of roads is to travel from one place to another quickly! This is potentially a very large cost, and should be fairly tractable for you to estimate: look at the average length of time spent commuting, calculate how much longer journeys will take, and multiply by the average wage for motorists.
There are also other costs, in particular from the required increase in traffic stops. You note the cost of hiring more enforcement officers, but not the the stress of getting pulled over—most people are not used to getting arrested. Because officers typically have a lot of discretion in who they pull over, and what ticket they write, enforcement can be uncertain, arbitrary and unfair. Additionally, they can be dangerous: when approaching a car the policeman has none of the typical situational cues they use to evaluate a situation. They can’t see the person’s body language ahead of time, and weapons are easy to conceal. At some point they are probably going to ask the driver to reach into the glove compartment, which is a not uncommon place to store a firearm.
A couple of observations related to your points from Freetown, Sierra Leone (I’m not too sure if this would be similar to the locations considered here). First, there are lots of traffic jams. My journey times are _much_ more heavily dependent on the amount of traffic than speed limits. It’s pretty rare that there’s open, good-enough roads to get up speed (but when there are, drivers go pretty fast). Second, the police pull drivers over regularly—usually for no reason other than to check the driver’s license (as far as I can tell). It’s common that the police ask for money regardless of whether you have your license (e.g. it’s easy to say they saw you breaking some rule—the driver can’t do anything other than argue or pay up).
Hi, thanks for your comment and apologies for the somewhat belated response!
On increasing travel times—yeah I think this is a really interesting point and something that we didn’t consider when modeling the CEA. I think it may be best to discount the income effects of this intervention as a result of this. After a quick Google search, I have found some data on this from the UK—“Each 1 mph reduction in average traffic speed costs the UK economy in excess of £1Bn in lost productivity through extended journey times” (https://www.abd.org.uk/press-release-hes-proposed-motorway-speed-limit-reduction-to-60mph-borders-on-economic-vandalism/). This suggests the impact could be quite significant, though as the World Health Organization found that the economic impact of road traffic injuries is approximately 3% of GDP, I think the economic impacts would still be net-positive.
Clare’s point on traffic jams is an important consideration here, both for your point and for the promise of this intervention—if drivers are never getting up to the speed limit, then decreasing them looks less promising. This was a concern we were aware of, but we felt unable to address from our desktop research, but this is something we will highlight to the founders of this organization, and it is something that they will be able to assess when doing country scoping visits.
Perhaps these considerations make advocacy on seat-belt legislation look more promising than advocacy to reduce speed limits. This would be good to pass on to the potential founders so that they can weigh up these considerations.
On the stress of getting pulled over by the police, I am not sure I can comment usefully on this as I don’t know too much about it, but thanks for raising the concern, and thanks Clare for the insight from Sierra Leone.