Monday, 18 November 2013

London's Cycling Fatalities by Hour of Day

Fifth cyclist killed in nine days. HGVs and buses are disproportionately represented in cyclist fatality statistics and 2013 is particularly shocking with so many killed in a short space of time. The number of cyclists on London's roads is increasing, as are the resulting death and injuries.

One of the themes being discussed amongst cyclists ask if there is something immediate that can be done until better separated infrastructure can be built. Should HGV's (Tipper Trucks in particular) be banned from the rush hour when the most cyclists are commuting?

One site I read (memory fails me) suggested that London's night-time lorry ban caused HGV's to come onto the road just at the same time that cyclists are commuting. London does indeed have a Lorry Control that bans HGVs of 18 tonnes or more between 9pm-7am Monday to Friday, and from 1pm Saturday right through to 7am Monday. In 2011 Paris has had zero cyclist fatalities and people are now looking to emulate their HGV ban.

I have a copy of the government's STATS19 collision database and have the ability to query the data for myself. I decided to see if the data supports an immediate ban of lorries during rush hour.

A few things you should be aware of:

The graphs I show below are for fatalities only.

I initially pulled data for the Inner London boroughs where most of the cycling deaths that have hit the news have occurred. The numbers were too small for any reliable patterns to appear so I have expanded to greater London. The data below is for the 33 London boroughs shown on their map.

Again to get a acceptable amount of numbers I have used the years 2005-2012.

To see the raw numbers I have been working with. See my Google Docs spreadsheet.

Fatalities per hour of day

The first graph I have created summarises the fatalities by:

  • hour of day along the X axis. 8 means 8am-8:59am.
  • shows the quantity of each vehicle type stacked on top of each other (not all reaching up from a zero base) that were involved in fatal cyclist collisions.

At the bottom, dark blue shows the number of fatality collisions involving cars and taxis.

The orange colour shows HGV's greater than 7.5 tonnes. From 8-8:59am, there were twelve HGVs involved in cyclist fatalities.

Green are buses involved in fatal cyclist collisions.

We can see a pattern emerging - the morning particularly between 8 and 9am is bad.

Adjusted for number of vehicles

Ideally we would cross reference this data with the amount of cyclists and other vehicles on the road during each hour.  I haven't yet found a source for that data.  However, I have found:

TfL: Average daily traffic flows on major roads in London by vehicle type.
I used data from 2010, see table 2.

Vehicle Type1000sPercent
Pedal cycles0.461.54%
Car and Taxi23.779.24%
LGV <7.5t3.5511.87%
HGV >7.5t1.344.48%
Bus and Coach0.662.21%

The numbers tell us that 79.24% of the traffic on London's major roads are Cars & Taxis, with HGVs just 4.5%, and buses 2.2%.

To get a sense of how much danger each vehicle type is bringing to the roads, I have divided the number of fatalities by number of thousands of vehicles. For example, the 12 HGV's 8-8:59am divided by 1.34 equals 8.96 fatalities (over 8 years) per 1000 HGVs per day.

The effect of looking at fatality rate per vehicle type is that cars and taxis because there are so many almost disappear from the graphs.  

What immediately pops out is the amount of danger brought by HGVs 8-8:59am, and also a disproportionate amount of danger throughout the morning.

Bus danger also pops out, but not so consistently.  There may be some interaction with the number of cyclists on the roads at these times. It requires further investigation before any conclusions can be made.

Motorcycles are also bringing some danger during the morning and evening rush hours.

But overall, London does have a measurable problem with HGVs causing cyclist fatalities. Separating them by hour of the day could reduce fatalities and serious injury significantly.


  1. Can you explain the sharp drop in fatalities at lunchtime, between 12 noon and 1pm?

  2. Hi, would be good to chat. I am doing the same. In 2012, there were only 3 deaths in peak hours I believe. Indicating overall trends may be changing. And indicating that overall far more cyclists are killed "off peak" when (potentially) the more vulnerable cyclists are on the streets (and less experienced cyclists).

    In London, pushing more lorries into non peak times (07:00-10:00 and 16:00 -19:00) may create higher concentration of “rushed” lorries on faster (and less busy roads), and create a greater danger to less experienced cyclists who tend to cycle off-peak.

    Have you all individual London cycle fatality data records so I could review?

    And to assess the “total” accidents “non-peak” and “peak” hours per year to see the trend.

  3. Sorry. "far more" was the wrong expression above.

    Between “peak (am+pm)” and “off peak” hours, then total cycle fatalities broadly appeared the same, in the 2012 and 2010 data. But I really would like to check with your data. Plus, the trend for Fatal+Serious, had the same broad split (peak v’s non-peak times). When you review “Slight” accidents, the peak times are more dominant, and ties into the fact that more cyclists cycle at peak times.

    But, I remain concerned, that pushing “more” lorries out of peak into “off peak” times, will create greater conflict with less experienced cyclists, and the total number of lorries will be concentrated into even more rushed with less hours to operate in.