“Black Cab” (*1/2 out of four) was a grim horror melodrama about a couple (George Bakhari and Synnove Karlssen) who get into a taxi with a jovial cab driver (Nick Frost) and realize too little/too late that he’s a deranged nutjob. By now- I think there have been several too many films about psychotic cab drivers so they simply aren’t too scary anymore. Watch Martin Scorsese’s “Taxi Driver” for more scares and thrills.