There are hardcore committed commuters on here that would tell you to claim the lane and ride through the construction zone. If it is congested to the point of the traffic moving under 25 MPH, that is actually a good route to take. But otherwise, not so much. Drivers already angry about being slowed below 60 MPH by the construction zone would only be angrier at you for slowing them even further - especially if there is no room to pass you.

Using the park-n-ride doesn't defeat the purpose if you are left with a decent commute. I live 30 miles from work so I drive 15 miles, park, and cycle the rest. I have cycled the entire 30 miles but it took an hour and forty five minutes - I just don't have that kind of time. By driving part way I spend 50 minutes pedaling, 20 minutes driving, and I'm home 35 minutes sooner, which is an hour and ten minutes of saved time round trip.

If, however, the part you drive leaves you with less than 30 minutes of cycling time, then yes, it's kind of pointless.