The phrase "to reach the pedals" means being able to touch and control the pedals in a vehicle, like a car or a bicycle, with your feet while sitting in a comfortable position. Full definition
Would you start driving if your feet didn't reach the pedals and your arms didn't grip the steering wheel comfortably? (canadianbusiness.com)
If you are shorter, the seats may not move forward enough so that you can comfortably reach the pedals. (classicgaragedfw.com)
Both the rear passengers can stretch their legs without hitting the front seats, while the driver wouldn't even reach the pedals if the concept actually had any. (topspeed.com)