Annex: Level crossing and road risk compared |
Note by Professor Andrew Evans, Specialist Advisor
1. In order to place the risk at level crossings
in perspective, it is desirable to find a means of comparing LC
risks with road risk.
2. One way of doing this would be first to estimate
the road safety fatality risk of a typical car trip or walking
trip without a level crossing, to form a baseline. Then it could
be supposed that the journey required the traverse of one level
crossing, and the additional risk imposed by the level crossing
could be compared with the baseline risk.
3. This can be done for both typical car journeys
and typical walk journeys, though various simplifications have
to be made. Table 1 gives the data and calculations. The column
headed "source" gives either the external source of
the data or a calculation from other figures in the table. The
alphanumeric sources such as NTS0409 are references to DfT statistical
tables (NTS = National Travel Survey).
4. The bottom line of the table gives the additional
risk from the presence of one level crossing on an average car
or walk journey as a percent of the baseline road risk. For car
journeys, the additional risk from the level crossing is estimated
at 7.6% of the baseline road risk, which is modest. For walk journeys,
the additional risk from the presence of a level crossing is much
larger. It is estimated to be 114% of the baseline road risk,
implying that the LC roughly doubles the risk of the journey.
5. This in turn is because the risk per level crossing
traverse is much higher for pedestrians than for vehicle occupants.
Based on LC fatalities over the decade to March 2013, row (k)
of Table 1 estimates that there were 1.35 fatalities per billion
LC traverses for vehicle occupants and 30.1 fatalities per billion
LC traverses for pedestrians, which was about 22 times greater.
Pedestrians make about one eighth of the number of LC traverses
as vehicle occupants, but they have just under three times the
number of fatalities. However, it is notable that the road fatality
risk per kilometre of travel is also about 20 times greater for
pedestrians than vehicle occupants - see row (d) of Table 1.
6. In conclusion, if a typical car journey includes
a level crossing, the crossing imposes an additional fatality
risk estimated at about 7.6% of the baseline road risk. If a typical
walk journey includes a level crossing, the crossing imposes an
additional fatality risk estimated at about 114% of the baseline
road risk. However, because a typical walk journey is much shorter
than a typical car journey, it is less likely to include a level
crossing. The fatality risk per LC traverse is estimated to be
22 times greater for pedestrians than for vehicle occupants. This
ratio is roughly in line with the road fatality risk per kilometre
for pedestrians relative to vehicle occupants.
Table 1: Journeys and fatalities with car and
walk as main mode (2012)
|(a) Trips/person/year with given main mode
|(b) Km/person/year with given main mode
|(c) Average length of trip with given main mode (km)
|(d) Road fatalities per billion person-km
|(e) Road fatalities per billion trips
|(f) Road fatalities per single trip
|Level crossing traverses
|(g) LC vehicle or pedestrian traverses per year
||NR LC database||12.38E+08
|(h) Average car/van occupancy
|(i) LC person-traverses per year.
|Level crossing fatalities
|(j) LC Fatalities per year 2003/04-2012/13j
||ASPR Chart 187||2.6
|(k) LC fatalities per person-traverse
|LC /road fatalities comparison