Traffic Freeway Signs

So there are these signs around Southern California that are up so that amber alerts for child abductions can be posted, but most of the time they post the time between freeway interchanges:

However, it almost always seems to be inaccurate.  Last week, coming home around 10:00 PM, with absolutely no traffic, the sign said I had 9 minutes to the next interchange.  Usually, during rush hour on that same route, the sign claims only 7 minutes!  It usually takes more like 25.  In Japan and China, there are some great highway signs that would be nice to have around here that show you a traffic map with routes and with colors for traffic density, making it easier to make quick decisions on different routes to use:

You would think Los Angeles would have such a thing already!