Yeah the grouping system just isn't made for roads, simple as that. Sure it should probably give you a popup or something, maybe auto-ungroup or not allow you to group them in the first place instead of locking up the game, but the grouping system was made for simples to be grouped together so you could create your own custom objects (in future you will probably be able to upload custom objects created from groups to the workshop). If you need to edit multiple road pieces, just select the multiple pieces instead of grouping them. Aside from saving groups as custom object, grouping doesn't give you any extra control over those objects beyond just selecting them.

The only reason I use group on roads is so I can bend multiple roads as one. Example: the three colored glass edgeless roads in the video, I would group them together then bend them to the desired shape. If you just shift click them then try to rotate them 90º they will all still rotate independently (sometimes clipping). If there is a better way other than doing each one at a time I would like to know. Currently the process is: Group, Bend, Un-group, Extend, repeat.

You can just create the 1st road then duplicate them to match.Be sure to connect each node then select the ones you want to duplicate.
grouping with track nodes never works out. editor needs a mass track node working with multiple splines option but that may never happen.

Originally posted by fzeroman:

You can just create the 1st road then duplicate them to match.

You can't really do that if you want the roads to bend differently (such as making the tracks 'yaw'). You need to keep the track nodes aligned to do that.

I usually group each set of track pieces rather than the nodes, and ungroup the section that I want to modify. I don't extrude the track, I duplicate the group and connect it up manually. (A auto-connect touching nodes feature would be nice for this)