NEW YORK (MONEY magazine) - Because of the high stakes involved, it can be difficult to decide when not to spend money on safety technology. After all, the lives of you and your family could be saved by one of these options.

But some technologies touted as "life saving" are little more than pricey gadgets that do little or nothing to protect human lives. These are a few that I think aren't worth the investment.

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Several luxury car makers are proud to tout headlamps that pivot in the direction you turn the wheel. On paper it sounds great -- who doesn't want lights that "peer around curves"? Yet in my driving, the benefit has been less than illuminating.

The adaptive lights do little or nothing to improve the nighttime view, even on dark and winding country roads where you'd most expect to see some difference. For now, available headlight systems are either standard on models like the Lexus LS 430 or part of pricey option packages.

As an $800 stand-alone option on the "entry level" Audi A3, it's not worth it, and its lack of tangible driver benefit makes me skeptical that it will ever trickle down to less expensive cars.

Infiniti was first to offer a system that reads lane markings and alerts a driver who's straying off the road. Initially, I found it an intriguing idea that merited development, but ultimately it doesn't seem worth the price or the annoyance.

The system worked well enough, audibly chiming and flashing a small light when I'd wander from my lane without first using the turn signal. But the camera can't pick up road markings that are indistinct or obscured by dirt or snow.

And it often nagged me when I wasn't asking for its help. Yes, the system can be shut off with a button, but if you're always turning the thing off because of false alarms, what's the point?

Some automakers are touting night-vision systems that, using an infrared camera and a dash-mounted screen, can display people or animals that are beyond the range of headlamps. I've tried several systems, and the safety benefit seems dubious. On a dark two-laner, should I really be looking at a dashboard screen? Am I not better off just watching the road?

Fact is, modern, high-intensity (sometimes called "bi-xenon") headlights already do an amazing job of lighting up the night. For now, consider night vision another gee-whiz gizmo to give automakers techno bragging rights -- and help them pocket a grand or three from gullible buyers.

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The street smart 15: The best cars of 2006.

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