Central Oxford is severely space constrained. It suffers from bus and vehicle congestion, and not enough space is provided for people walking or waiting for buses or admiring the buildings, for proper bus layovers, or for safe cycling routes. Creating more space is not an option, so there is no way to do anything about these problems without shifting people from the least space efficient mode — private motor vehicles — to more efficient modes — buses, bicycles, or feet. One key tool for achieving this would be an access charge for motor vehicles. That would also help to reduce air pollution and noise.
A "carrot" approach such as subsidising the bus system would be highly inefficient — much of any subsidy would go to existing bus users, not just switchers — and is not target-mode neutral — it would push people to use buses instead of walking or cycling.
I suggest that an access charge should be quite ambitious, not a simple congestion charge, and should attempt to capture as many of the negative externalities of motor vehicles — the costs they impose on other people — as possible, to make an effective Pigouvian tax.
The negative externalities take several forms: there is the space motor vehicles require on the roads (and the space taken by the roads themselves), there are the emissions from their engines (and from tyres and brakes), there is noise, there is road damage, there is danger to people walking and cycling. So an access charge, enforced though Automatic Number Plate Recognition cameras, could be based on vehicle:
- weight (to capture road damage costs)
- size (to capture the space occupied, but also as a proxy for danger posed to people walking and cycling)
- emissions (to capture the costs of air pollution)
- time of day (to capture congestion costs)
There could be exemptions (or discounts) for residents and blue badge holders. But in general this charge should cover all motor traffic, with uniform and consistent rules. Electric vehicles would pay much less than diesel ones for emissions, but would still be paying for space and congestion and road wear. Making buses pay a charge would provide an incentive to bus companies to consolidate routes. Taxi trips should be more expensive in peak periods. Tourist coaches should be paying for the privilege of loading and unloading inside the city centre. And so forth.
Any access charge needs to deter enough motor traffic to prevent congestion, most importantly to allow buses to move freely even in peak hour, and to free up space for pavements that are wide enough for people to walk around Oxford comfortably and safely, and for separated space so cycling into or through the city becomes an option for anyone who can ride a bicycle. A charging system really needs to be implemented alongside a reworking of the traffic flows along the lines of the Phil Jones proposals, giving space currently used by private motor vehicles to buses, in exchange for space currently being used by buses going to people walking and cycling. Implemented solely as a way to reduce congestion and force a modal shift from private cars to buses, a congestion charge might work technically but would have much less impact, benefiting too restricted a range of people to be politically viable.
The proceeds from a charge could be used to fund park-and-ride facilities, including bike storage and bus stops and cycle tracks into the centre. Some of it could go to fund respiratory health at the NHS Trust. Some of it could go to road maintainance. It should not be used for subsidies to advantage some bus users over others (as current park-and-ride bus charging does).