Motor-vehicle seat belt with built-in electronics

In combination:

• a motor-vehicle safety belt formed as a flexible longitudinally extending band and formed with a longitudinally extending and laterally substantially closed passage, the belt having an upper face extending continuously over the passage and a lower face extending continuously and smoothly underneath the passage such that the passage is not visible on the lower face;
• an insert fittable into the passage and comprised of a flexible and elongated support strip and at least one electrical or electronic element usable by a motor-vehicle passenger employing the belt secured to the strip, the upper face being formed at the element with a region through which sound can pass more readily than it can otherwise pass through the belt;
• and
• anchor regions on the strip adapted to be welded to the belt for securing the strip to the belt.