As part of the emergency active travel funding, the cycle tracks on Magdalen Bridge have been widened. On Wednesday evening (August 5) I went and had a look at the changes for myself. There I ran into Chris (Pedal&Post) and we watched the interactions between motor traffic and people cycling for maybe half an hour, from 5.30 to 6pm.
What are the changes? The cycle lanes on the bridge — and a short distance on either side — have been widened, maybe from 1.5m to 2.4m (based on the plans below, I didn't actually measure them). And the centre line has been removed. There are also large cycle symbols in each of the cycle lanes.
How does it work? Traffic speeds seemed to be lower than before, but that's hard to judge (and may be a temporary effect due to the unfamiliarity of the layout). And it looks more inviting for people cycling — I could just about imagine cycling here with my seven year-old now, getting her to keep left and holding the outside of the lane behind her.
The new configuration may be marginally better for people walking, as there seemed to be fewer people cycling right on the kerbline.
The major concern is that, with the central carriageway just 4.6m wide at narrowest (from the plan), two buses are unable to pass one another without entering the cycle lanes. For two cars this is possible, if only just for large SUVs, though drivers may be tempted to swerve into the cycle track to increase their separation from oncoming vehicles, rather than slowing down. But two buses can not physically pass one another without entering the cycle lanes, which poses a real problem if they meet each other when those lanes are full (with cycles overtaking one another, or simply with peak-hour two bicycle wide densities).
There are about 10,000 motor vehicles a day here at the moment, and historical counts suggest 14,000 a day (see below).
Something like this approach has also been implemented on Windmill Rd, and something similar is planned for Abingdon Rd. I haven't seen those yet, but with far fewer buses it might work better on those routes (assuming the widths are the same). The key there is likely to be continuous provision.
Since the changes have just gone in, people are mostly encountering the new layout for the first time and their behaviour may change once they are accustomed to the layout. Most likely they will become less cautious and drive faster.
Traffic is still not back to pre-lockdown levels and it is August, without most undergraduates but with nothing like normal tourist numbers. So both cycle and car and pedestrian numbers are significantly lower than potential peaks. The Oxbike counts for the 24 hours to 8.30pm that day were 7,600 cars; 4,500 cycles; 4,100 pedestrians; and 2,500 buses - but the last (2018) historical DfT traffic counts/estimates were 12,000 cars/vans, 12,000 cycles, and 2,100 buses.
I saw one "snapshot" with relatively dense traffic. The dynamics will be very different at low traffic levels. If there's no traffic going the other way, many drivers are likely to do 30mph here (as they currently do) and some may drive faster with the missing central line removing the "constraint" of a narrow traffic lane. When faced with oncoming traffic, some of these drivers are likely to use the cycle lane rather than slow down. But the wider cycle lanes may increase the passing distances to people cycling.
There's a risk of "observer interference". I'm pretty sure at least one bus driver started veering into the cycle lane and changed their mind when they saw Chris obviously videoing them on his smartphone and me pointing a moderately large camera at them.
The Broader Context
There have been no changes on either side of the bridge, either to the Plain roundabout or to the horrible bit of High St between Magdalen College and the Botanic Gardens. The westbound cycle lane there just disappears, and people cycling to Longwall have to cross a lane of motor traffic and then filter between traffic lanes, while the eastbound lane is dangerously narrow (worse than Magdalen Bridge itself was before the current changes).
So, however it works out, this change isn't by itself going to do much to enable more people to cycle. We really need that bus gate on St Cross or South Parks, to reduce motor traffic enough that the right-hand turn lane at Longwall can be removed, freeing up space there for adequate cycle lanes, and so the Magdalen Bridge entry to the Plain can be narrowed to a single lane, allowing reconfiguration of the roundabout along Dutch lines (as has been done in locations in Cambridge and Manchester).