Black Friday shopping, of course, means Black Friday crowds. Bangor police are reminding people to prepare for long lines, heavy traffic and delays, especially along Stillwater Avenue and the mall.Extra police patrols will be the area to monitor traffic and cutback on crime. Police say you can do some things to make the shopping experience safe, too. Such as shop with cards and not cash. Money in hand can make you a target for thieves. Don’t leave your purse or wallet unattended. Keep valuables in the trunk of your car and lock the vehicle.Park in well-lit areas. And if you’re stuck in traffic, especially around the mall, don’t call 911 to report that, unless there’s an emergency.