Stockholm Congestion Tax System

Key Facts

• To make the charging system work, the SNRA and the city had to find a way to recognize, charge and receive payment from vehicles. With help from IBM and its partners, a plan was devised to charge vehicles as they passed control points on the way in or out of the Stockholm city center during weekday, rush hour times. The city implemented a free-flow roadside system using laser, camera and systems technology to seamlessly detect, identify and charge vehicles.
  

• As part of the free-flow roadside plan, 18 roadside control points located at Stockholm city entrances and exits identify and charge vehicles depending on the time of the day. The tax per passage was SEK 10, 15 or 20 (about $1.50 to $3.00) depending on the time of day. The highest amount charged was during rush hours, from 7:30 to 8:29 a.m. and 4:00 to 5:29 p.m. The maximum amount per vehicle and day was SEK 60, or about $8.50.

  Key aspects of the solution include:
  

  • When crossing into the inner city via one of 18 entry gates, cameras take a photo of the front and rear license plates, using optical character recognition (OCR) to identify vehicles through a central database in Copenhagen.
  • There is a second OCR engine reading the number plates if the first system can’t identify it. Success rate is >99%.
  • There is also an onboard RFID transponder, which receives a signal from the gate transceiver, capturing the time, date and tax amount.
• The project took 12 months to implement
• It was successful for the citizens because it was easy to see, they saw the benefit from day one. It is also very important to ensure accuracy and confidence with the system.

What was the impact?

• Comments on energy savings

  Greenhouse gases such as carbon dioxide have fallen by 40 percent in the inner city and by two to three percent in Stockholm County

• Comments on other resources saved

  • By the end of the trial, traffic was down nearly 25 percent
  • reduction in air pollution by 8-14%
  • The government’s plan is to devote revenue from the tax to completing a ring road around the city.
• The project has independent verification for results

Making it Happen

• The following regulations or incentives allowed the business case to be more attractive

  Stockholm, Sweden is a city of islands, meaning they cannot keep building to keep up with population growth (Stockholm County is growing at a rate of around 20,000 people a year). Traffic congestion has been a growing aggravation for years, with over half a million cars traveling into the city every weekday. So the City Council decided to implement a congestion pricing system on a trial basis in 2006, and it was voted to be made permanent in 2008.

• Barriers experienced during the initiation of the project

• Comments regarding barriers

  Optical character recognition (OCR) was a difficult problem, but IBM identified software through their global R&D centers, and had a solution in 2 months

• What were the key lessons learnt?

  The success of the congestion tax in Sweden is the result of a very close cooperation between the people at the Swedish Road Administration and IBM.