As a result, the booths on the Kent side were removed and the charge is now only payable online, by post, or in participating retail outlets.

The crossings are operated by Connect Plus Limited on behalf of National Highways as part of a 30-year Design-Build-Finance-Operate agreement that began in 2009.

[8] North of the river, the rail line High Speed 1 (between St Pancras and Ebbsfleet International Stations) passes under the approach roads at a near right angle.

[10] It has been described by the Highways Agency as "a vital transport link for the national and South East economies",[11] by the former Secretary of State for Transport, Patrick McLoughlin, as "a crucial part of the country's strategic road network",[12] and by the local Thurrock Council as "one of Europe's most heavily used crossings and complex traffic management systems".

[17] The crossing and its approaches, like most UK urban motorways, are equipped with lane control and variable-message signs to manage traffic.

The next nearest vehicle crossings to the west of Dartford are the Woolwich Ferry and the Blackwall Tunnel, both well within East London.

When the bridge is closed in high winds and for maintenance, no convenient diversion exists through London for the higher-limit southbound vehicles.

The proposed Thames Gateway Bridge to the west was provisionally supported in 2004,[19][20] but was cancelled in November 2008 when Boris Johnson became Mayor of London.

[22] The Lower Thames Crossing is a proposed tunnel to the east between Shorne, Kent and South Ockendon, Essex.

[40] Although the website for paying the charge is operated by the UK Government, the contract for the free-flow charging system is held by French public roads operator Société des Autoroutes du Nord et de l'Est de la France (SANEF) on behalf of the Government.

[42] Initial reports at the start of the year suggested a crossing between Tilbury and Gravesend, replacing a ferry service,[43] but this had been rejected by July in favour of a route further upstream, near Dartford.

After negotiations with the Ministry of Transport, Kent and Essex county councils obtained government approval to increase the previously set tolls in 1960, before opening.

[53][54] The Dartford Tunnel Act 1967 (c. xxxvii) gave a joint committee of Kent and Essex county councils (the Dartford Tunnel Joint Committee) the authority to increase the tolls, and in December 1977, the toll was raised from 25p to 35p for cars, 40p to 55p for two-axle goods vehicles, and 60p to 85p for HGVs.

[56] That year, Michael Heseltine, then a junior transport minister, announced that a second tunnel would be built in conjunction with the North Orbital Road, later to become the M25.

[61] In 1985, the Transport Minister, Lynda Chalker, announced that the number of toll booths would be increased to 12 each way, but concern grew that two tunnels would not be able to cope with the full demands of a completed M25.

[68] The concession was scheduled for 20 years from the transfer date, with a stipulation that it could end when debts had been paid off, which was agreed to have been achieved on 31 March 2002.

During construction of the approach road, a World War II bomb was found in its path, which required closure of the entire crossing.

[77] In 2000, the European Union issued a directive that value-added tax should be charged on all road tolls, including the Dartford Crossing.

[80] In October 2009, the Government announced its intention to sell the crossing as part of a public sector deficit reduction strategy.

[82] After the change of government following the 2010 general election, the new prime minister David Cameron announced that the crossing might still be sold, despite local opposition, particularly from Gareth Johnson, Member of Parliament (MP) for Dartford.

[84] Pre-pay accounts for the crossing were introduced around this time; drivers held an electronic device called a DART-Tag in the vehicle that automatically deducted the charge at payment booths.

[93] In September, the Highways Agency announced that the new scheme would start to operate at the end of November, though related works to remove barriers would continue until April 2015.

[34] The Dart Charge scheme was considered a success by the project management, who claimed it has reduced peak-time round trips over the crossing by 15 minutes.

The Automobile Association said the scheme had faults, while a 2015 BBC report showed 1.8 million fines had been issued for failure to pay in the year since the charge was set up.

[95] In 2023, a system upgrade prevented many users from paying the Dart Charge, and National Highways temporarily extended its payment deadline to accommodate the problem.

[98] There is currently one bus service that uses the crossing, the X80 operated by Ensignbus which runs between Lakeside Shopping Centre and Bluewater.

The design was criticised for failing to protect any passenger from falling off the vehicle, and running costs were estimated at £2,550 per month, with only £45 revenue.

[103][104] The introduction of the ADR scheme initially caused confusion, and for a short time, transporting aerosols through the tunnel was banned.

[105] Certain hazardous goods vehicles, together with some oversize and abnormal loads (if permitted), may require escorting by National Highways traffic officers.

[112] Because the design capacity has been exceeded, the crossing is subject to major traffic congestion and disruption, particularly when parts are closed because of accidents or bad weather.