Here are some modifications I made to the car transporter in the Highway Transport set.
I really like this set and it bugged me that lego had made such a fantastic looking set with bad technical flaws, namely the steering.
About this creation
As you can see here and in the main picture I have got rid of the middle set of wheels on the tractor unit. I have filled in the gap with 2 yellow fuel tanks. I have also replaced the existing wheels with model team wheels. The rear axle is now twin wheel base.
Here I have replaced the original 3 piece windscreen with the model team 1 piece one. I have also moved the windscreen wiper arrangement.
To make this rig steer better I have replaced the original long axle with 2 shorter axles. This allows each wheel to turn independently.
On the trailor I have replaced the original axles with four shorter ones to allow the wheels to turn independent of each other. This also makes a vast improvement on the steering.
I would have also liked to change these wheels to model team ones but I just don't have enough of them.
Hey Andrew, thanks for the kind words in both of your comments! To the windscreen problem for 7-wide trucks: of course, you can "surround" the problem like I did on the cab-over semi. But what I´m gonna try on a future model is the following: using two clear-transparent 2*1 panels (2 bricks high, two studs wide), placed sidewards, subdidivided by a thin plate (2*1 studs) and borded by the same plate on each side - that makes a six-wide front shield. Next step: adding one shift of transparent plates/tiles to the sides to extend the windscreen further back. Then you should be at a width of about seven studs! Not sure yet how to most effectively fix the whole thing, though... Or, check out Ralph Savelsberg's awesome cab-over semi: http://www.flickr.com/photos/madphysicist/3857196008/in/set-72157607099231255/
I´m not sure how he actually fixed the shield - I´m gonna ask him...