A year after an unruly crowd trampled a worker to death at a Wal-Mart store, the nation’s retailers are preparing for another Black Friday, the blockbuster shopping day after Thanksgiving. Along with offering $300 laptops and $99 navigation devices, stores are planning new safety measures to make sure the festive day does not take another deadly turn.

Last year, frenzied shoppers at a Wal-Mart in Valley Stream, N.Y., trampled Jdimytai Damour, a temporary store worker who died soon afterward. To prevent any repeat, Wal-Mart has sharply changed how it intends to manage the crowds.

That new plan, developed by experts who have wrangled throngs at events like the Super Bowl and the Olympics, will affect how customers approach and enter the stores, shop, check out and exit. Each store will have its own customized plan. The hope is for an orderly Black Friday, a seemingly incongruous notion.

The most significant change at Wal-Mart is that the majority of its discount stores (as opposed to its Supercenters) will open Thanksgiving morning at 6 a.m. and stay open through Friday evening. Last year, those stores closed Thanksgiving evening and reopened early Friday morning. By keeping the stores open for 24 hours, Wal-Mart is hoping for a steady flow of shoppers instead of mammoth crowds swelling outside its stores in the wee hours of Friday.