In many cases you can feel how the energy of the T-junction literally "hits" the house with sharp, aggressive, Sha chi quality energy. This happens especially if the house has no landscaping around it and it is very close to the road.
The other variable will be a short road with very light traffic, in which case the negative effects will be minimal, if any at all.
In feng shui, the traffic on the road is often compared to the flow of the river. The stronger the traffic, the stronger the river flow. This is an easy way to feel, or imagine the energy rushing into the house. The difference, though, is that with the river you get high quality energy, even if rushed, and with cars you get high pollution.
Are there good feng shui tips to improve the T-junction house?
Yes, first it is always a good idea to check the flow of Chi in your home, as well as apply at least the basic feng shui home tips.
Second, see what you can do on the outside, as well as on the inside regarding the T-junction energy. Smart landscaping to protect your front door, as well as any windows that are "hit" by the rushing energy is the best feng shui solution.
You can also neutralize/soften the energy from the inside. For example, have a row of plants on the windowsills of all windows that are facing the road. One or several crystal clusters can do a good job in a window of a house facing the T junction.
Many feng shui consultants recommend a bagua mirror on the outside of the T junction house, see if you like this feng shui cure for your house.
A similar challenging feng shui situation is occurring with the Y-junction houses, but with a slightly less challenging feng shui. A Y junction house can create a "missing opportunities" energy for people living in the house, thus it is important to activate and balance its energy on the outside, as well as on the inside.
If you have a question about using feng shui, please ask your question at the feng shui forum.