Motorists have reported problems trying to pay the 'Dart Charge' after National Highways introduced a new system to manage payments.
The charge, which has been in place on the A282 since November 2014, allows motorists to pay for their crossing in advance or by midnight the day after they cross the Thames.
Customers reported not being able to access the website from the 27 July and were greeted with a message saying they would have until midnight yesterday (1 August) to pay the charge.
National Highways has now confirmed the majority of the problems are resolved and has also now extended payment deadlines for motorists.
What happens if you need to pay the charge?
National Highways has confirmed that the original payment deadline has been extended till the 15 August for non-account holders.
The Dart Charge contact centre and website has been experiencing an exceptionally high demand and systems have been running at capacity.
If you need to make a payment the advice is to use the website. A queuing system was previously in use - but National Highways have confirmed users should be able to access the site normally as of Wednesday morning.
Motorists who would prefer to call have been warned of long queues to get through to a person at the contact centre.
What if I already have an account with Dart Charge?
Drivers who hold an account with Dart Charge will have to login and revalidate their payment cards to ensure they don't receive a Penalty Charge Notice.
Any crossings that have been made during the down period will be available to view on the website.
If a payment card is not revalidated it will not function. This can be done until August 31.
Motorists with an account should have been notified about the update, including instructions on what they need to ensure their account is active.
What has National Highways said about the outage?
National Highways apologised for the disruption.
A National Highways spokesperson said: "The Dart Charge websites and customer contact centres are all operating.
"We apologise for the service issues users have faced over the last few days and have implemented service improvements. While customers may still experience short delays, the average online wait time is now less than 5 minutes.
"We have further extended payment deadlines to ensure everyone has sufficient time to pay the charge. Dart Charge account holders have until 31 August to update their card details on the website.
"Non-account holders who use the crossing between 27 July and 14 August have until the 15 August to pay the charge.
"We apologise again for the inconvenience which was due to essential system updates."
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