Traffic count data for Grovelands Road collected during a week in December 2018 has provided hard evidence about the large amount of traffic using this residential street and the number of drivers who are breaking the 30mph speed limit. Every day some 1,300 vehicles used the road. Nine people were recorded driving at more than 50mph, including three who were doing more than 60mph. The highest speed recorded was 70.4mph.
Traffic counts were carried out at 11 locations in December 2018. To date, data has only been published for Grovelands Road
The data, obtained by a Grovelands Road resident from Enfield Council, shows traffic counts broken down into hourly segments for the week of 12th to 18th December. For each segment the data breaks down the vehicle counts according to speed.
The total number of vehicles detected was 9,129 - on average 1,300 a day. 1,241 vehicles were breaking the speed limite (around one in seven - an average of 177 per day).
In peak hours more than two drivers a minute were using the road. Even during the busiest hour of the entire week, with around 70 vehicles going in each direction, 14 drivers broke the speed limit - and this was at the very time when there would have been children returning home from school.
The table below shows totals for the whole week. (.)
Traffic counts in Grovelands Road, N13, for the week 12-18 December 2018
Download Excel workbook containing detailed source data
Speed (mph) |
Northbound |
Southbound |
Total |
4161 |
4968 |
Vpp85 |
29.5 |
29.6 |
Mean |
22.8 |
23.4 |
SD |
6.9 |
6.5 |
0-5 |
3 |
5 |
5-10 |
131 |
119 |
10-15 |
445 |
365 |
15-20 |
750 |
947 |
20-25 |
1244 |
1588 |
25-30 |
1035 |
1256 |
30-35 |
396 |
511 |
35-40 |
116 |
129 |
40-45 |
31 |
37 |
45-50 |
5 |
7 |
50-55 |
3 |
1 |
55-60 |
1 |
1 |
60-65 |
1 |
1 |
65-70 |
0 |
0 |
70-75 |
0 |
1 |
Vehicles = 9129 |
Posted speed limit = 30 mph, Exceeding = 1241 (13.59%), Mean Exceeding = 33.85 mph |
Maximum = 70.4 mph, Minimum = 0.7 mph, Mean = 23.1 mph |
85% Speed = 29.58 mph, 95% Speed = 33.78 mph, Median = 23.32 mph |
10 mph Pace = 19 - 29, Number in Pace = 5335 (58.44%) |
Variance = 44.54, Standard Deviation = 6.67 mph |
"By no means the worst rat-run in the area"
The Grovelands Road resident who obtained the data described it as "staggering". Clare Rogers of Better Streets for Enfield commented:
"This data presents a picture of a street that is hostile to walking, cycling and residents' well-being. Speeding aside, the sheer volume of 1,300 vehicles a day prevents this from being a truly healthy neighbourhood street, where any age can walk or cycle and people tend to stroll in the middle of the road: that transformation happens at around 300 vehicles a day. And we know that Grovelands Road is by no means the worst rat-run in the area."
A "safe" speed, but only for some...
The Vpp85 data in the table (the 85th percentile) is used by traffic engineers to assess the speed which feels appropriate for most drivers when traffic is flowing freely. The speed that feels safe to drivers will depend on factors such as road width, how straight the road is, how far they can see etc. In this case Vpp85 was below the speed limit (but only just).
But drivers are judging safety in terms of the risk to occupants of cars, in particular themselves, and the occupants of a large car or SUV travelling at 30mph would be pretty safe driving along Grovelands Road. The risk to people in the category referred to as "vulnerable road users" is, however, very high at 30mph. A pedestrian - such as a child unexpectedly emerging from behind a parked car, or a cyclist knocked off their bike - is highly likely to be seriously injured or killed if hit by a car going at 30mph. If speed limits in urban areas are set at 20mph - as is increasingly common, but not in Enfield - the chances of surviving with minor injuries is high.
So, given that the primary function of roads like Grovelands is to provide access to people living there, it is irresponsible for the Council to set the speed limit at 30mph. A much more appropriate limit would be 20mph, if necessary backed up by measures which would cause drivers to go more slowly - speed humps, road narrowing, obstacles like planters (but at intervals along a long straight road, not just at either end).
So what about the "quieter neighbourhood"?
The December traffic counts were carried out to provide baseline data so that the council can do a proper "before and after" assessment of the effectiveness of their "quieter neighbourhood" measures. So far these merely consist of planters placed at the ends of some streets, including Grovelands, which are supposedly intended to deter through drivers, but the signs rather paradoxically "welcome" them to "our street".
Unlike the thousands of cars that drive through the Lakes Estate every day, the rollout of the quieter neighbourhood measures has been very slow and, anecdotally at least, they have had little or no effect on traffic volumes or speed. Hopefully, similar baseline data gathered at ten further locations will soon be released. It will almost certainly show that the "neighbourhood" is anything but quiet (higher speeds create exponentially more noise) and, with so much traffic, not really conducive to neighbourliness. High time for a serious attempt to tame the rat-runners.