There’s also an ‘auto’ regen setting to which the car defaults – not just in electric mode, but in others as well – in which it seeks to regulate brake energy recuperation for itself based on data coming from the navigation system and on what it can work out about your distance to the car in front using its forward sensors. Mercedes isn’t alone in trying this as a means to boost energy efficiency – although rarely do you find it integrated independently of an adaptive cruise control system (something the A250e only gets as an option).
It’s a problematic execution mostly because, when the car is running in Hybrid mode, the brake pedal becomes unpredictable. With the car’s tendency to coast defined entirely automatically, you’re never totally sure how much ‘engine braking’ you’re going to get when you lift your right foot on approach to a junction or roundabout; or, indeed, how much ‘recuperation’ the car is going to do for itself in stop-and-go motorway traffic.
With that abiding sense of uncertainty present, the A250e then presents you with one of the least progressive and intuitive brake pedals this tester has ever encountered. I’ve known cars that ‘prime’ the brake pedal when the frontal crash avoidance system thinks you may be in danger of an accident, with knock-on effects on pedal feel; but this A-Class’s ‘blended’ brake pedal seems to juggle electrical recuperation in and out of the initial pedal travel, and ramp friction braking response up and down, with widely unpredictable results. Perhaps it does make the car a smidgeon more efficient and maybe it will help you avoid an accident one day. Frankly, I’d much rather the car had simply been smoother and easier to drive.
Running under a mix of electric and combustion power, the A250e has Individual, Sport, Comfort and Eco driving modes. It has good initial throttle response in all of them, although the way the piston engine and eight-speed gearbox somewhat lazily respond to bigger pedal inputs in the more laid-back modes might make Sport your default choice for quicker out-of-town motoring.
The car’s outright performance level is strong, particularly when picking up from lower revs in higher manually selected gears, when all that electric motor ‘torque fill’ is poured in. The fairly hard-working 1.3-litre engine doesn’t like revving hard, though. It’s noisy and harsh beyond 4000rpm and, more than anything else, that is what’s likely to limit how interested you’ll be to drive this car with any enthusiasm.