In October 2022 a few members of Push Bikes cycled from Selly Oak to Perry Barr to look at new cycling infrastructure (a so-called cycling infrastructure safari). In particular, we looked at Selly Oak, the link from Cannon Hill Park to the A38 blue route, and the extension of the A34 blue route to Perry Barr.
The Selly Oak Triangle junction was remodelled a few years ago. Initially the plan was purely to "improve traffic flow and reduce pollution". Push Bikes objected, and the plans were changed to include cycling infrastructure. The result is generally good result for cycling, and most of the problems could be fairly easily corrected. However, it's worth dealing with the elephant in the room.
The previous design of the Selly Oak Triangle was dreadful. For me, as a driver, the worst part was the arrangement in Chapel Lane outside what is now Homebase (photo right), which appeared to have been designed by someone who liked crashing cars together as a child. This was exacerbated by making Chapel Lane part of a gyratory system. So the junction badly needed remodelling for motor vehicles. However, that is a safety issue. It is a mistake to increase junction capacity if one's aim is to reduce pollution, because doing so attracts more traffic, something known as induced demand. As people change their habits to take advantage of the "improved" junction, so it fills up with more traffic until the delays through the junction return to the level they were before. However, since there is more motor traffic at a (near) standstill, then pollution will be greater. As can be seen from the photo of the old junction, there have long been traffic jams at the Selly Oak Triangle junction, it's just that now they are bigger.
Of course induced demand applies to all forms of transport, including cycles. Dutch authorities struggle to cope with induced demand for cycling. However, there is a world of difference between inducing demand for cycling, and inducing demand for driving. Cycles cause almost no pollution, and being much smaller than cars they use less street space per person (public transport is better still in this respect, but as I have said previously, public transport is not suitable for all journeys). Whilst electric cars might address the pollution issue, they have the exact same potential to cause traffic jams as do internal combustion engine cars.