Buses could be the unsung heroes of the low-carbon revolution and are the best answer we have to mounting congestion.

But buses are unloved. For much of the population, they are a mode of transport used only when other options are unavailable. The more affluent you are, the less likely you are to hop on a bus.

In the post-Second World War period, as British people prospered, bus travel went into a half-century-long decline. In the past decade there has been the beginning of a revival with the introduction of concessionary travel and the construction of bus lanes. But if more travellers are to be lured from their cars, bus services need to be frequent and reliable, and buses must be clean and comfortable.

Worryingly, as The Herald reports today at the start of a major series, bus travel has declined since 2007 in response to the recession and in particular because there are fewer shoppers and shop workers to transport. The knock-on effect has been the quiet axing of some routes, while service frequency on others has been cut. This threatens a spiral of decline as more passengers desert. Once lost, it is very hard to win them back, so this is more than a temporary blip. Also, this reversal in fortunes is hitting bus-company profits, threatening investment in new, comfortable, less polluting buses.

Meanwhile, congestion and blocked bus lanes create problems with timetabling and reliability. With its new city-centre shopping mall containing 1700 car-parking spaces, Aberdeen is a classic example of what happens when car travel is prioritised. Because the city centre is choked with traffic, a bus journey that takes 20 minutes one day may take 40 minutes the next. It is a shameful indictment of public transport policy that many road journeys into Scotland’s city centres take longer now than in Victorian times. To add insult to injury, competition between operators tends to produce bunching, with long gaps followed by several buses at once, as they play “cat and mouse” in the quest for ­customers. And while many rural communities have few (if any) bus services, overprovision in city centres causes extra pollution. That is why Glasgow’s Renfield Street has some of the poorest air quality in Scotland.

Labour’s answer lies in the partial re-regulation of bus services, with companies buying bundles of routes and cross-­subsidising profitable ones with unprofitable ones. However, that means either higher fares for everyone or much higher subsidies – something ­unimaginable in the current financial climate.

The SNP used to favour re-regulation but ditched the ­policy around the time Brian Souter of Stagecoach became a major party donor. Now both the SNP and bus operators favour a partnership approach, in which both parties agree ­minimum quality standards. Glasgow is about to adopt such a partnership, in which operators agree to minimum standards on timetabling and the quality and age of vehicles. It is hoped this will take older, polluting vehicles out of the city centre, tackle wasteful emissions and end irritating cat-and-mouse tactics.

Better buses should lure more motorists from their cars. But similar arrangements elsewhere have broken down over the issue of public investment. And, ultimately, they can work only if bus-lane discipline is enforced.

There is much more debate in Britain about rail expansion, and high-speed rail in particular, with bus travel considered a local issue. Yet most journeys are short hops to work or the shops, and railways can never reach into all communities.

Buses have a difficult image problem. They are perceived as grubby and unpleasant. Yet, given a makeover, well-run, high-occupancy buses should be a key part of the response to climate change at minimal public cost, as most services are unsubsidised. The more people who use them, the better the experience will become, as a virtuous circle of popularity and investment is created. We need to learn to love the bus.