If you currently drive into Cambridge, why would you support a congestion charge? Probably for one of two reasons: the journey time is sufficiently shortened to be worth paying for (like the M6 Toll); or you’re given an alternative that is better value than driving now.
Whether either (or both) reasons hold depends largely on how much value you attach to your time. Academic research into this is based on surveys in which people choose between travel options that are either faster but more expensive, or slower but cheaper. This informs the official figure used in the UK, currently £13/hour for commuting trips. (Other trip types have different values.)
That figure is just an average though: the value you put on your time is likely to be different. The less money you have, the less you are willing or able to spend to save time. For the very poorest, the trade-off might be with paying for food or heating.
So, how does this apply to a congestion charge? Imagine it costs £10 to drive into Cambridge at peak times, but your round-trip commute by car becomes 20 minutes quicker. Rationally, you would pay the charge if you value your time at £30/hour or more. Otherwise, you will be excluded or feel aggrieved if you do not have a better-value alternative.
Assuming you need a car anyway; that parking at work is free; and the petrol cost is £1.50. The cost to drive is £11.50/day. Now, imagine you can travel by bus for £5/day, but the return trip takes 30 minutes longer than driving. If other factors balance out, do you pay a £6.50 premium to save 30 minutes? Rationally, yes – if you value your time at £13/hour or more. So, about half of people with those two options will choose to drive, and half will take the bus.
What about people who don’t have that choice and value their time under £30/hour? The travel time saving is simply not enough to compensate for having to pay the congestion charge. That is why local authorities must provide good-value travel options for everyone before introducing a congestion charge.
This article was first published in the Cambridge Independent on 13 November 2019.