The traffic is even worse than I'm saying here. I am 30 miles north of both Dallas and Ft Worth The two cities are side by side east and west of each other. I 35E goes from Denton to Dallas. I 35W goes to Ft Worth. If I leave Denton at 6 AM for Dallas, I will get there in 25 minutes. If I leave at 6:10, it may take two hours or more.
If I am in Dallas, I can leave at 3PM and get home in about half an hour. If I leave at 3:30, it may be 6 PM before I get home. Traffic is always bumper to bumper all the way to Denton where it disperses.
The same is pretty much true with respect to traffic between Denton and Ft Worth but not quite as bad except on race days at the Texas Motor Speedway near Alliance airport on 35W. Then it can be worse than 35E.
Yes, traffic is heavy and scary. We lose about 1 motor cycler a month.
Always try to time your passage through DFW at around 9AM and/or 2PM and you won't have much problem. But, the traffic always is moving between 60 and 80mph. You can receive a citation if you go too slow.