Minimum number of long tunnels

The best option is probably to leave the driving to a professional driver, eg, a train driver :-)

I have been driving for many years but lately due to my eye weakness, I get nervous with lights inside closed areas especially for long tunnels. I have no problem with < 2 km tunnels.

It is early cataracts. But now I have no choice but to go back to Interlaken then to Geneve to return a rented car before flying back home. I just need to know which route with shorter tunnels. I hope some one help me ASAP. Thanks.

If it is a french rented car see if you can return it in Colmar in stead. If you really have suddenly developed sight problems you should not drive.

I found this website for RVers, with a map showing tunnels. https://alanrogers.com/articles/camping-caravan-road-trips/major-mountain-roads-tunnels-passes-europe#interactive-map-of-mountain-roads-passes-and-tunnels
It doesn't show any tunnels between Colmar and Interlaken, which seems a little suspect.
I understand you're in a bind, but I would really look at dropping the car off (maybe in Basel?) and getting on a train.

You do not say what you whole itinerary is. Are you renting the car in France and returning it to France? You do know about getting a Swiss vignette.

The Belchen Tunnel on the A2 between Basel and Olten is 3.2 km. That looks to be the longest tunnel on the route.

There are tunnels as you go under Basel and one as you avoid the centre of Bern.

There are also several between Basel and Olton, and then sharply downhill towards the Olten junction of motorways.

At all of these you can take regular roads over or around the obstacles but they will be much longer and in the case of the area around Olton involve mountain driving with switchbacks and steep roads.

Unfortunately Switzerland is honeycombed with tunnels. Lots of mountains and big hills and both trains and highways prefer level and straight. The quickest way to go straight is to dig through the obstacle, or in the case of Basel, Bern and Luzern, put the highway under the city.

Sorry

Many thanks to all who tried to help and as well to others who advised me not to drive. Thanks God, I was able to overcome the problem by waring anti-reflective (AR) coated glasses. I have reached Interlaken yesterday.

I'm glad you made it.

Strasbourg - Colmar - Basel - Bern - Interlaken is a journey I make frequently by car.

Glad you managed the tunnels and the steep gradient towards Olton OK.