Traffic flow, driving tests and the introduction of the new 08 numberplate could be disrupted by a strike of 8500 Department for Transport (DfT) workers.
The strike by members of the Public and Commercial Services (PCS) union is in response what they consider to be poor pay rises and appraisal systems.
Traffic flow management will be affected as many of the strikers work for the Highways Agency's regional monitoring centres.
A spokesman for the HA said: 'We are monitoring the situation to see how many staff will take action, so that we can ensure the level of service we normally provide can be maintained.'
Anyone booked to take a driving test this Friday is being advised to still turn up.
Chief executive Rosmary Thew said: 'Not all examiners are members of the PCS union and even if they are, we cannot be sure that they will not turn up for work.
'We therefore want candidates to attend so that practical tests can be delivered if possible. Theory tests are not affected and will be taking place as planned.'
Disruption to the introduction of the 08 numberplate on March 1 is expected to be minimal, although some registrations may be delayed by the strike action.