Mark's Musings

A miscellany of thoughts and opinions from an unimportant small town politician and bit-part web developer

Traffic management during Abbey Bridge Closure – a few reasons why it is what it is

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With further delays to the re-opening of Abbey Bridge, one of the things that’s repeatedly cropping up on social media is the question of why the current traffic management system was chosen. In particular, people want to know why we have the crossover at the end of Oat Street, instead of reversing the flow in Oat Street and Swan Lane.


The main reasons for rejecting the two options of either reverting to two-way traffic along Swan Lane or reversing the flow in Oat Street and Swan Lane are essentially practicality and safety.

Taking safety first, reversing the flow of a one-way street (or making it two-way) is something that is very strongly recommended against by the relevant guidelines as statistics show that doing so almost always results in a sharp rise in accidents. There are five significant traffic outlets onto Swan Lane (Conduit Hill, Rynal Street and three car parks) as well as several commercial sites accessed from the street. If traffic was flowing the other way, it only takes one forgetful motorist to fail to look in the “wrong” direction for there to be a collision. (The objection to this objection, so to speak, is that traffic will be nose-to-tail anyway, so it would be hard not to spot that it’s going the other way. But there are quieter times, and the main accident risk would be overnight when traffic is much lighter).

By contrast, there is only one road (Mill Bank) which exits onto Mill Street, one house and one business. The Mill Bank junction is closed for the duration of the works anyway (and safety is the main reason why), so that means a significantly lower accident risk by restricting the two-way flow to this section.

Using Swan Lane for eastbound traffic, either as a two-way road or by reversing the flow along with Oat Street, would also require temporary traffic lights on the High Street junctions as well as on Mill Road, as well as repainting (or coning off) new lanes on the High Street to handle the different flow patterns. Two way traffic along Swan Lane would require removing all on-street parking from it, which would have seriously detrimental effects on adjoining property owners.

Another issue is the bus station. This is on High Street between Swan Lane and Oat Street and, because of the way that the routes work, there are more buses using it in a southbound direction direction than northbound (and hence there are three southbound stands but only two northbound stands). All the buses need to use the diversion during the closure, and with the chosen option southbound buses simply turn left down Oat Street after leaving the bus stops. Northbound buses turn left out of Swan lane and loop round by using Merstow Green roundabout, leaving them on the right side of the street for the stops. That’s a slight diversion, but it’s less convoluted than making southbound buses loop round and then turn back on themselves.

Reversing the flow in Oat Street would also need traffic lights at the High Street end. And that would be additional to the existing lights at the Swan Lane junction, as they would still be needed to handle traffic to/from Avon Street. So we’d end up with two sets of lights in close proximity, close enough for the queues to interfere with each other. There’s also the problem of access to the semi-pedestrianised service road which runs along High Street in front of the shops, parallel to the main road. At the moment, to get to that, traffic turns into Oat Street from the High Street and then right into the service road. If service traffic had to do so against oncoming traffic from Oat Street, it would mean more complex traffic management and traffic light patterns.

Another problem with reversing the flow in Oat Street is that it’s only one lane wide. At the monent, traffic exiting Swan Lane into the High Street splits into two lanes, one turning left and the other turning right. That means that two vehicles at a time can exit into High Street. And, even during the work, there’s still a significant amount of left turning traffic. If westbound traffic was going via Oat Street, then all the traffic would need to queue in a single lane irrespective of which way it was turnning and only one vehicle at a time would be able to exit into High Street. That means that to get the same throughput, the lights would have to be green in that direction twice as long as they currently are. It also means that the queue, being half as wide, would be twice as long for the same number of queueing vehicles. So it would be far more likely to tail back into Mill Street, which still has to be one-way because it isn’t wide enough to handle two-way traffic round the bend at the bottom of the hill. So the tailback from Oat Street would get in the way of traffic from Swan lane wanting to go down the hill towards the bridge.

On a side note, it doesn’t help to say that Mill Street used to carry two way traffic as normal, and therefore could again without traffic lights. Firstly, the fact that it didn’t do it very well was one of the reasons why it was changed in the first place, and, in any case, the road has been deliberately narrowed since then. It would need rebuilding to allow two-way traffic around that corner again.

Using Oat Street for eastbound traffic makes it much simpler, as none of the existing lanes and lights on High Street need to change – all that’s necessary is a sign to direct through traffic down Oat Street instead of continuing along High Street to Abbey Road. And simplicity is itself a big factor; it’s easy for those of us who know Evesham to think of alternative routes but whatever is chosen has to somehow be communicated to visitors as unambiguously as possible – and that means not only putting up temporary signs saying what to do, but also removing or covering any existing signs and road markings which conflict with the temporary route. The more complex the changes, the higher the probability of someone getting it wrong – which takes us back to the safety issue, because mistakes lead to accidents.

Greater complexity also comes at greater cost, and, given that the funding from central government is solely for the construction of the new bridge itself, the costs of managing the traffic during the closure will come out of our council tax contributions. So keeping things cheap and simple is a valid goal in itself.

Individually, none of these reasons may be compelling in thmselves (although the safety aspect is probably the most important, and the chosen solution is one which was favoured by the emergency services). But, taken together, they make a very strong argument against any solution which involves reversing the flow in Oat Street or using two-way traffic in Swan Lane. Which is why those options were considered, but rejected.

Incidentally, one of the other options which was considered, but rejected, was to make no changes at all and require all outbound traffic to go round the by-pass. I think, on balance, that what we’ve got is better than that!

While we’re on the subject, it’s also worth explaining a bit more about how the traffic management is working at the moment. Far from being paid to stand around doing nothing, as some people have suggested, the “orangemen” are actually key to the operation of the one-way system. Rather than operate the lights on a simple timer or close-range vehicle detector (which is what’s normally done at roadworks), the orangemen are manually controlling the lights in order to balance out the flow. All of them are in radio contact with each other, and the two operators of the lights themselves take instructions from the “spotters” about the lengths of the queues at each end, and then switch the lights in order to always give the side with most traffic queueing priority. Where they can, if there are no large vehicles in the queue, they’ll also allow short bursts of two-way traffic along Mill Street to maximise capacity. The lights are only on a timer overnight when traffic is lighter.