The drive-over instrument, launched by WheelRight, takes the effort out of tyre pressure checks and its developers believe it could bring "huge safety benefits", too.
The pilot, organised in partnership with the Highways Agency and Welcome Break services, is now due to run for three months on the southbound side of the M6 services.
"The Highways Agency has identified tyre pressure under-inflation as a major cause of accidents on the UK's roads," states John Catling, WheelRight's chief executive.
"We are delighted to be partnering with them to deliver automatic, free tyre pressure checks for commercial and private drivers at Keele," he continues.
"The simplicity, ease, convenience and speed of the WheelRight system will encourage drivers to check their tyre pressure's more regularly, without the need to get out of the vehicle."
Two WheelRight systems have been installed at Keele, one in the HGV area and another for private motorists. A team from WheelRight and the Highways Agency is available to answer driver's questions on tyre pressures and how to use the system.
To get free tyre pressure readings, drivers are being encouraged just to drive over the embedded WheelRight instrument.
Results are available automatically in seconds either on a touch screen or paper print-out. Should tyres require immediate attention; drivers will be able to use the nearby air compressors at Keele Services.
Alongside the obvious safety issues, poor inflation can also impact fuel consumption, which increases on average by up to 5% if tyres are just 20% below their recommended pressure.