North of San Diego along the I-5 freeway are large yellow signs with the outline of a string of three people running: a woman holding the hands of two small children. These warn drivers that migrants might suddenly dash in front of vehicles in an attempt to evade authorities. A few miles out of town, traffic slows as vehicles heading north fan out among what look like toll booths. There are no tolls, but those with brown faces or who look suspicious are checked carefully. Drivers with white faces are sometimes asked if anyone else is in the vehicle; more often they are simply waved through. This is another reminder of Life Conditions faced by Mexican immigrants struggling to find a foothold in California and the US, and of the crisis facing the USA.