I've been waiting there 2 times, one evening after 5 pm and the other morning starting around 10 am without success.
I was asking all people getting fuel, but most people are just living around the neighborhood. And indeed it is a very crowded place, because people around getting there postboxes from there.
Some few were willing to take me, but were heading north - and I wanted to go south.
I didn't try it with a sign, but there is no good space for cars to stop at the road.
I wouldn't try again there - or maybe it just takes much longer waiting time.
I went to the roundabout at the "centro comercial Lagoh" and I got a lift within 15 minutes to Jerez