Thursday, November 08, 2012

Driven to distraction by technology


Hella Lane-Change Assistant
There's usually a hidden downside to new technology. When Hella Corp. unveiled its Lane-Change Assistant system for automakers, Audi grabbed it immediately, introducing it as Side Assist on the 2007 Q7. Competing systems arrived soon after and within a few years,  Blind Spot Warning (BSW) technology was appearing in dozens of production vehicles from several car companies.

All perform the same function, warning drivers when a lane-change maneuver is ill-advised. Some designs use cameras; one employs lasers, a few others ultrasonics to scan adjacent lanes. The Hella system uses radar instead. Microwave radar is less affected  than vision-, laser- or sonar-based designs by blowing dust, rain and other environmental factors.

There is one notable downside, however: Hella chose the identical 24-Gigahertz K-band radar frequency used by police radar guns. Any radar detector confronted by, say, the Side Assist of an Audi A7, will scream a warning in response. Although the signal is low-powered, in tests we found that a sensitive radar detector will spot that Audi BSW from up to 1,000 feet away. Follow one in traffic and the alerts are unending.

Mercedes created yet more microwave pollution by incorporating similar K-band radar into its Distronic Plus adaptive cruise control (ACC) system. Accompanied by a separate 76-GHz radar, used for long-range distance measuring and speed computation, the K-band radar in Distronic Plus will also drive a detector nuts
 
Culprit: Hella K-band radar
If that weren't enough, roadway traffic-flow sensors monitoring vehicle density and speeds also began using K-band radar. Mounted on poles at regular intervals, these gadgets provide realtime traffic data via wireless links to city and state transportation departments. Drive north from Denver on I-25, for example, and expect  a K-band alert every mile or so for an eternity. Similar early systems were first installed on I-10 west of San Bernardino (CA) and and they're growing in number nationwide.


How to deal with this onslaught of spurious signals? Escort created a feature dubbed TSR—Traffic Signal Rejection—that counters traffic sensors. Found in most Escort and BEL models, we've tested TSR and it works. But what about those other K-band problem signals?
Escort 9500ci with laser jammers on Lamborghini

The only partial fix we've identified to date is found in a couple of remote models, also from Escort.  These are the Passport 9500ci and its clone from sister company Beltronics, the BEL STiR Plus.

There's no magic bullet incorporated into either detector. But their combination of GPS, a radar antenna tucked away in the grille area and some very smart signal processing does result in fewer false alarms, particularly when installed in an Audi.


These remote models enjoy more traditional virtues like stupendous radar range, a near-absence of false alarms, red-light camera protection, standard laser jammers and by virtue of being built-in, immunity from theft and official scrutiny. They're pricey but worth it, the reason why I've got one of each installed in my daily drivers.

I've reviewed these two detectors separately in past stories; now there's a new, condensed review covering both models. Even if you're not yet pestered with microwave-based safety gadgets, both detectors offer some compelling technology of their own.