Some great footage of the storm at maximum intensity:
The Jarrell storm, in a more documentary-like format:
In the second video, shortly after the 3:00 mark, you can see the backup of vehicles on I-35 as the storm raged just a mile or so away from the highway -- the result of this decision from highway patrol (the photo referenced in the passage is visible at this link):
Another, more glaring, example was documented in central Texas during the Jarrell TX tornado event on 27 May 1997. The photo in the slide was taken looking northwest. The beginning of the Jarrell, TX, F5 intensity tornado is seen as the slight cone-shaped lowering in the cloud base. As this tornado was developing, vehicles can be seen in the foreground parked near the overpass on I-35, apparently to seek shelter from the storm under the bridge.
In addition to the traffic jam in the photo, the Texas State Patrol created an even bigger one when they stopped both northbound and southbound traffic on I-35 in anticipation of the tornado moving southeastward, and crossing the highway. Although the intentions of this action were certainly good, the huge chain of vehicles at a standstill created by this action could have resulted in a major disaster had the tornado deviated from its south-southwestward movement and moved southeastward. Nearly 5 miles of stopped traffic created a would-be sitting target for this tornado!
My nephew was born just a couple of months before this historic storm, and my sister, at the time, lived in Austin, which is just down 40 miles or so down the interstate (and in the path of the cell, which eventually dropped an F4 tornado in the Austin suburb of Cedar Park), so I've always held a certain fascination towards the Jarrell tornado ... the especially terrifying thing about this storm was how many people within its path did everything that they were supposed to do (that is, seek shelter within the confines of an interior room, putting as many walls as possible between themselves and the exterior walls), and were still obliterated when the entire structure was swept from its foundation.
I do not in any way condone one attempting to flee from a tornado, but the unfortunate reality of certain violent tornadoes is that if you're in the crosshairs, and you sustain a direct hit, you're probably going to die. With that in mind, if you're extremely confident that you have the means and opportunity to escape such a tornado (say, with a relatively traffic-free chunk of the interstate readily accessible to you in a rural area), and, once again, you're fairly certain that you're looking at an extremely violent tornado bearing down on you, it's probably worth trying to get the hell out. That does not mean that you should try to hop on 635 and make a quick getaway when a long-overdue violent tornado hits DFW, because if the traffic congestion ahead of you doesn't get you killed when the storm overtakes you, the heart attack you'll have during your attempted getaway will.
Also, that damn video where those idiots took shelter under an overpass from a Kansas tornado has gotten way too many people killed. You'd be better off trying to run on foot out of the path of the approaching tornado, and then, assuming you hadn't found adequate shelter by then, flattening yourself against the ground and protecting your head ... or, even better, driving the hell out of the way. There's even some new thought that staying in your car might sometimes be a viable option for survival, although there doesn't appear to be any kind of consensus on whether jumping into a ditch or staying in your car is better from a survivability standpoint.
But, yeah. Be well, Jarrell. Be at peace.