Camera tracking, Cinema 4D Lite/Cineware that comes with AE and 10 or 20 hours homework, and practice spending the first 20 minutes with the Learn Workspace in After Effects and some time with the User Guide are all that is required to pull this off.  After Effects is a complex app with a complex UI and just pointing you to a single tutorial about camera tracking is just the tip of the iceberg. 

If you are a hobbyist and you want to integrate 3D models into video an open-source (free) solution that is extremely capable is Blender. 

Combining a drawing or illustration with film requires a very good understanding of perspective and the principals of hand-drawn animation. Camera tracking does not help much with that, but Motion Stabilizing does.

By far the simplest way to create your project is to start with the camera tracker. The other cars on the highway are going to be tagged with tracking markers that will throw off the accuracy of the track. You'll need to remove most of them to get an accurate camera track.  When the trackers have been removed from most of the other vehicles, pick the frame in the shot where you want to put the virtual bridge and have it pretty close to Full Frame, add a layer marker so you can find the frame easily again, then select some camera tracking points on the roadway that make the target align perfectly with the highway, use those points to set an origin and ground plane, then use those same points to create a solid and a camera. The next step is to open the reference solids layer properties and resize it so that it covers most of the road, add the grid effect, and make sure the origin and ground plane are accurate. 

You can then use that ground plane layer to accurately place your 3D layer containing the bridge. I would use a shape layer as a place holder because that will give you more options. Once you make sure that your bridge layer is tracking perfectly you can start thinking about how you want to make the layer look 3D.  You can use that 2D bridge as a starting point and create a bunch of drawings or animate different components of a shape layer, or you can set up lights to match the scene lighting, then export the comp as a C4D file and end up with a good way to create a simple 3D object that will match the scene. 

Let us know how you decide to proceed and we can probably point you in the right direction. Be very careful about any tutorials you watch. Most of the newer ones are presented by enthusiasts that don't really know how to explain things and they can get you in a lot of trouble and waste a lot of your time. 

My natural response is also to look into camera tracking as Byron said. 

Watch this video, what you need to make is the same using the Track Camera tool and the "Create Solid and Camera" option to after replace it with your footage, this option instead of "Create Text and Camera". You could also use "Create Shadow Catcher and Light" to give more integration to the environment of your video.

Add 3D element to video footage

Could be as simple as swooshing along an elongated solid with blur and overlaying it with reduced opacity and using blendig modes like multiply to create a faux shadow. Basic AE stuff essentially. Otehr than that you might want to read up on basic image stabilization to eliminate vibrations to make things easier. Just don't get lost in complex 3D tracking tutorials or whatever. That would be pretty much useless here, given the nature of driving along a motorway. everything else beyond that is really much more about understanding traditional perspective and possibly a bit of AE's 3D space, limited as it may be, along with basics like masking, keyframing and understanding how effects operate.

Mylenium