except when passing /except passing

[bmo]

Drivers must keep to the right lane except when passing another car.
Drivers must keep to the right lane except passing another car.

Is the bottom one incorrect?

[blacknomi]

I think so.

But the greeting is more important than an answer!

Hellooooooooooooooooooo!

[AintFoolin]

Drivers must stay/keep in the right lane unless they are passing another car
The left lane is only to be used for passing

gosh, i wish more people followed this. Nothing more annoying than a 'rolling roadblock' that's going 10mph under the speedlimit

[bmo]

I think so.

But the greeting is more important than an answer!

Hellooooooooooooooooooo!

Aha, long time no see. Thanks a lot.