The White House Office of Management and Budget has asked the NHTSA to review the requirement for new vehicles to be fitted with tyre pressure monitoring equipment fitted to the wheel and tyre assembly. The OMB states that most TPMS work on data sent by the ABS system, and that the added cost of the new system, may lead manufacturers to stop fitting ABS to vehicles on a cost based argument. The NHTSA proposes that vehicle manufacturers phase in a direct pressure monitoring system, replacing existing indirect systems, over the next four years.