Can you use active cruise control on A roads?

[Zippee]

Had ACC on my old grand Cherokee and loved it, meant it took a while to find my current RS6 as many weren't fitted with it (CC is standard but ACC was part of the optional assistance pack) as It was a must have for me.

[shtu]

Ari said:

Another question, does it work at night and in heavy rain? (I'm guessing so since it uses radar, but curious to know).

Very much so. Those are the perfect conditions for it - wind the following distance out a bit and let the car keep a safe gap for itself. Snow causes problems if the sensor gets covered, but it simply won't engage if that's the case.

I've always said that busy A roads are arguably the best place to use it - there's many, many situations where overtaking simply won't be possible or necessary, so switch on ACC and relax.


(And for those wilful luddites - any of these automations can be overridden any time you like. I's a driver aid, not replacement.)

[Kenny Powers]

I use active cruise in all manner of situations, including stop/start through 30 mph urban streets. It's not always practical, or even desirable, but very often it turns a chore into a relaxing journey.

My car's self-driving feature also has the added bonus of not requiring any hands-on steering wheel interaction under 10mph, so really heavy traffic is an ideal opportunity to carry on with my Rubic's cube

[foggy]

Ari said:

Another question, does it work at night and in heavy rain? (I'm guessing so since it uses radar, but curious to know).

Yep, radar ACC is unaffected by lighting conditions so works just as well day and night. There are some camera only ACC systems (MINI and Subaru spring to mind) which are less effective in spray and darkness and withdraw themselves if they cannot ‘see’ sufficiently.

I was driving back through Germany once in heavy rain and spray - the Volvo radar/camera ACC I was using could detect cars ahead in lane and adjust my speed appropriately to keep distance, I couldn’t even see them! Radar/camera fusions systems are generally more robust, scanning laser (lidar) systems are just beginning to be introduced too. Camera also offers the opportunity for steering guidance support - I find some natural feeling, others very intrusive.