Useless Cruise Control Downhill...

[hihihi]

My 2005 LS430 is great at coasting, so speeds up when going downhill. Trouble is, even with cruise control activated.

Mine has ACC (AdaptiveCruiseControl), thus is perfectly capable of slowing (via fuel control, or, if needed, the gears and finally by activating the brakes), but only to maintain distance from another vehicle ahead that the radar has seen.

I wish I knew a way of telling the appropriate control unit to also listen to the speedometer.

Cruise control has an amazingly calming effect on me. Love that, and activate it as much as possible.

So, how nice would it be, to not have to worry about speeding when going downhill.

[1990LS400]

I guess you are going to have to buy an LS600h or one of the other Toyota or Lexus models with "Hybrid Synergy Drive". Vehicles with hybrid drivetrains go into regenerative braking mode when the actual speed exceeds the set speed on downhill slopes. The speed of our Prius seems to creep up by no more than about two mph above the set speed as indicators in the instrument cluster show that the hybrid battery is charging.

Unfortunately the regenerative braking may have a small impact on safety due to the brake lights not being activated during regenerative braking. When driving our Prius, I notice that drivers of following cars sometimes have to brake sharply to keep from hitting our Prius on downhill slopes as it automatically slows down.

Regardless, adaptive radar cruise control is a wonderful feature that makes driving much more restful - especially in a hybrid.

[hihihi]

It appears then that there is no way of reprogramming the appropriate control unit, nor any other aftermarket option to speedlimit my ACC. I've raised this issue on other LS-forums but also without success.

Thanks '1990LS400', you may well be right: forget my LS430 and look elsewhere... ...only my bank manager would rather I didn't! :)