The cost of using Bath's car parks will be based on the levels of pollutants cars produce in a new scheme which will be rolled out from Friday (September 8).

While some drivers will see no change in how much they pay, drivers of the most polluting vehicles could find that an hour's stay costs up to 90p more. The charges will apply to everyone using Bath's car parks, from residents and traders to tourists.

Bath and North East Somerset Council last increased the cost of parking in Bath in November, when tickets went up by 10p an hour. That was then only the second price increase in 12 years.

As the new "emissions based" charges are set to come into effect, here is everything you need to know about what this means for you.

How much will it cost?

The cost of parking in a car park will now vary significantly depending on your vehicle.

Drivers of electric cars and or a petrol car which emits less than 131g of CO2 per kilometre will continue to pay the current car parking charges: £1.70 for an hour's parking, £3.40 for two hours, and so on.

But prices will increase in line with a car's emissions, with petrol cars emitting more than 255g per kilometre seeing the cost of an hour's parking go up to £2 for an hour and £4 for two hours.

Diesel drivers, meanwhile, will have to pay an even higher charge. Even diesel cars which produce less than 131g of CO2 per kilometre will pay 50p more than current rates. Diesel vehicles emitting more than 255g per kilometre will pay £2.50 for an hour's parking and £4.50 for two hours.

In some circumstances, ticket machines may be unable to see your vehicle's emissions and may instead charge based on engine size. Petrol vehicles with engines between 0 and 1550cc will pay £1.80 for an hour's parking or £3.60 for two hours, rising to £2.10 for an hour and £4.20 for two hours for diesel vehicles with engines over 2951cc.

For diesel drivers charged by engine size the cost will be 50p higher for each ticket.

You can see a full breakdown of the costs on the consultation page for the plan here: https://beta.bathnes.gov.uk/emission-based-car-parking-charges-bath-car-parks

One the charges come into effect, you will be able to see them on the main parking webpage here: https://beta.bathnes.gov.uk/find-parking

Which car parks are affected?

The new parking charges will be in place at the following Bath car parks:

• Avon Street
• Bath Sports & Leisure Centre
• Cattlemarket
• Charlotte Street
• Claverton Street
• Green Park Road
• Kingsmead Square
• Manvers Street

No changes are planned at the city's three Park & Rides will remain free for people using the bus service. The council is hoping that the prospect of paying more for car parking in the city will encourage people with more polluting vehicles to use this service rather than drive into the city centre.

How do I pay?

You will have the option to pay at the ticket machine by cash or card, or through MiPermit.

New ticket machines are being installed which will ask for your vehicle's number plate. They will then automatically calculate and display the cost of your stay with your vehicle, before you are asked to pay.

You will not need a ticket, but they will remain available for people who want them.

Traffic wardens will have access to how long you have parked for in real time on their handheld devices.

What if I don't know my vehicle's emissions?

Drivers do not need to know their vehicle's emissions when parking, as the ticket machines will look up your vehicle's emissions from the DVLA database.

Parking charges will be calculated based on emissions where possible, but if these are not available they will be calculated based on engine size.

If your vehicle is not registered with the DVLA, such as is the case with foreign-registered cars, you will be charged the top rate by default. If the ticket machine is unable to reach the DVLA due to a system error, all cars would be charged the lowest rate.

If you want to know how much you will have to pay before parking, you can look up your vehicle's emissions from the DVLA yourself here: https://www.gov.uk/get-vehicle-information-from-dvla

What about season ticket holders?

The price of a season ticket for one of the affected car parks will now also increase in line with your vehicle's emissions. If you have a season ticket tied to multiple vehicles, it will be priced based on the emissions of the most polluting one.

The current annual charge for a car park season ticket valid all days of the week of £4,056.98 was introduced in November — to the shock of season ticket holders who had previously been paying £1,633. Now, for drivers of the most polluting diesel vehicles, the cost could rise to £5172.05.

People signing up for new season tickets will have to pay the new price right away but — following the Local Democracy Reporting Service's reporting of the previous season ticket hike — anyone with an existing season ticket will be able to renew it at the current price for 12 months before they have to pay the new prices.

Why is this happening?

The council's parking services team manager Andrew Dunn explained the thinking behind the policy to the council's Climate Emergency and Sustainable Policy Development and Scrutiny Panel on June 6.

He said: "The focus of the proposals is about pedestrian safety.

"They are designed to reduce pollution to protect the most vulnerable. They are also designed to incentivise the displacement of more polluting vehicles from our city centre to more sustainable alternatives, such as the park and ride sites, and in these cases the prices will remain unchanged. This will also help to reduce congestion on the network.

"Of course any reduction in emissions from the tailpipe of a vehicle will also have a beneficial impact on the climate emergency as well, but that is not the core reason for these proposals."

The council estimates it will make £225k a year from the increased charges, but Mr Dunn said: "This is not about raising revenue."

What does the council say?

Manda Rigby, Bath and North East Somerset Council's cabinet member for transport, said: "Prices won't change for a lot of drivers.

"This approach is being adopted across the country but we're the only council remaining committed to offering cash payments for customers. We see it as really important to protect this.

"Our overall aim is to improve public safety by improving air quality and reducing congestion and I'd like to thank all that took part in the consultation and shared their views with us.

"Air pollution currently causes up to 36,000 deaths in the UK each year and the consultation responses show residents are concerned about the air quality in Bath, which these changes will help improve.

"Introducing these new charges will also support our Journey to Net Zero ambitions [and] builds on the progress made by the Clean Air Zone."