patti lee has the latest police are saying and they can protect themselves. reporter: the crime wave is the reason police put up the sign. this warning everyone to stash their valuables in the trunk. but soon a more specific message will be targeted to those targeted most. reporter: on the shuttle bus at oakland international airport. tarsha brown listens to the audio messages playing over head. please make sure you have all your personal belongings and watch your step. reporter: but soon, people will be greeted with something more than a warning to protect them from crime. we have seen an increase in crime in this particular area. mostly what we have seen is individuals that may have just flown into the international airport. reporter: travelers and rental cars are stopping for a quick bite and leaving valuables out in plain sight like this navigation system on the dashboard. this is probably a rental car, right. reporter: the problem, tourists are often tire
their valuables in the trunk. but soon a more specific message will be targeted to those targeted most. reporter: on the shuttle bus at oakland international airport. tarsha brown listens to the audio messages playing over head. please make sure you have all your personal belongings and watch your step. reporter: but soon, people will be greeted with something more than a warning to protect them from crime. we have seen an increase in crime in this particular area. mostly what we have seen is individuals that may have just flown into the international airport. reporter: travelers and rental cars are stopping for a quick bite and leaving valuables out in plain sight like this navigation system on the dashboard. this is probably a rental car, right. reporter: the problem, tourists are often tired and in a hurry. most people just jump out, i m only going to run in and get this one little thing. some people leave the car running with the keys in it. kids in the ca