Greenlight call their chase cars “Green Machines”. They’re found across their entire range, including their accessories and dioramas. They’re generally 2% of any production.
They can be identified by the inclusion of emerald-green metallic paint on the body, chassis, rims, interiors or tyres. Some Green Machines have a combination. I’ve also seen the addition of extra irregular features, such as blue metallic rims.
Here's some examples:
The regular, and chase version, of the Hobby Exclusive - 1977 Chevy G20 Van - City Fire Department Paramedic.
Muscle Shop Tools Series 7 - Road Work Accessory Pack regular and chase version.