The numbers are only for the peak hours Mon-Fri. Vehicles per hour are in one direction. Traffic levels drop off significantly outside of these hours. Averages are median of 5 days totals.
Histon Road 30mph, Southbound towards Cambridge:
08:00-08:59 762 vehicles per hour, one car every 4.7 seconds. 24% >35mph.
09:00-9:59 790 vehicles per hour, one car every 4.6 seconds. 15% >35mph.
The amount of traffic arriving at Twenty Pence Road on the northern edge of Cottenham is 74% and 76% of the Histon Road levels.
Histon Road 30mph, Northbound returning from Cambridge.
16:00-16:59 378 vehicles per hour, one car every 9.5 seconds. 24% >35mph.
17:00-17:59 566 vehicles per hour, one car every 6.4 seconds. 21% >35mph.
18:00-18:59 695 vehicles per hour, ne car every 5.2 seconds. 18% >35mph.
The amount of traffic exiting at Twenty Pence Road is 56%, 60% and 57% of the Histon Road levels.
Before 9am has always had an more edgy and rushed feel to it - my instincts are right. My instincts also tell me that 8:50am is a terrible time for speeding, worse than 8:30am and I have wondered if this is the gonna-be-late-for-work effect.
I have also noticed that traffic in the 4pm slot is running faster and I have suspected the white van effect. A quick scan of the raw data suggests that Category2 vehicles (>6m long) are only 10% of the traffic on Histon Road and do not speed more than other vehicles. Exiting on Twenty Pence Road however, is a very different story, with a much larger proportion of vans and 10% higher speeds than category 1.
I've included the numbers comparisons for Twenty Pence Road as I sometimes wonder how much traffic is passing through the village as an alternative to using the parallel A10 trunk road. The A10 typically queues from just south of Waterbeach to the A14 roundabout and the B1049 offers a parallel route. It is interesting to note the lower percentages of traffic passing in the reverse direction in the evening which gives a little weight to my theory.
The section of Histon Road between the mini roundabout and the beginning of the cyclepath is exactly 1km. This equates to 2-4 minutes of cycling (10-20mph range). Assuming a rate of one car every 5 seconds, you are going to be overtaken by 24-48 cars on this stretch. With typically a fifth of cars speeding at 36mph or more, you can begin to imagine how many unpleasant overtakes a cycle commuter must endure if they cycle on the road. It's not just the speeding cars, there are a lot of drivers simply wanting to overtake and may get frustrated by a slower cycle and oncoming traffic preventing an overtake if you ride away from the kerb. Kerb huggers will have many of these vehicles squeezing through.
You can halve the number of unpleasant overtakes by cycling at a lycra roadie speed of 20mph. If you can't, that footpath must look like a safe haven, a necessity even.
I thought I might as well record how many cars pass me on this 1km stretch to see how it compares to the Police recordings. I normally spend 2.5 minutes on Histon Road.
October half term school holiday week (i.e. very quiet)
Southbound Mon 08:50am. Just 6 passes in 2.5 minutes.
Southbound Tues 09:20am. 7 passes. Feels like a Ghost Town compared to normal.
Northbound Mon 18:30pm. An unbelievable 5, yes just 5.
November, during school term:
Southbound Wed 8:50am. 12 passes. (plus queue after I pulled onto path)
Southbound Thu 9:00am. 11 passes + 7 queued behind.
Southbound Fri 9:00am. 6 passes.
Southbound Mon 9:30am. 12 passes. (very little oncoming traffic, overtaking easy)
Southbound Wed 8:55am. 8 passes.
Southbound Thur 9:05am. 9 passes.
Northbound Wed 6:50pm. 6 passes (had to wait for traffic to clear)
Northbound Fri 6:00pm. 0 passes (very unusual!)
Northbound Wed 7:00pm. 4 passes.
Northbound Thurs 7:30pm. lost count, was distracted by overtakes at high speed.
I give up! I lost count too many times when distracted by overtaking cars rushing to overtake in gaps that were too small. I'd end up concentrating on staying alive rather than being relaxed enough to count.
- Southbound, when a normal busy week there is enough oncoming traffic to prevent cars overtaking if you ride out from the kerb. If you ride in the gutter the queuing cars will squeeze through.
- Lack of overtaking opportunities because of oncoming traffic leads to frustrated drivers sitting on your tail right where you can't see them and where you feel most vulnerable.
- Northbound, at the end of the cyclepath there is often a wave of traffic that has been released by the traffic lights in Histon. Sometimes have to wait for the traffic to clear, sometimes it is clear then you get engulfed whilst on the road.