Google's self-driving car project plans to start winter-testing Chrysler Pacificas in the heart of the American automotive industry next week - in Detroit, one mile across the river from where they are built in Windsor, Ont.

Waymo is the name of the company, owned by Google parent company Alphabet Inc. Since 2012 it has already test-driven more half a dozen different kinds of autonomous vehicles more than 3.5 million miles in 20 cities in six states.

To date the winter driving has been around Lake Tahoe in Nevada and California, and in Washington State. But the self-driving system needs more experience interacting with live commuters coping with sleet and snow in a crowded urban environment. So Detroit it is.

After the first blizzard hits this winter - late December is about the earliest they can expect this - the company's system will know what it's like to start losing traction at 70 mph next to bumper-to-bumper semis on a crowded  freeway named after some pioneer of the auto industry. (All the Detroit-area freeways have auto-related names: Ford, Fisher, Reuther, etc.).

"We're aiming to give our technology more  practice driving in snow, sleet and ice," Waymo CEO John Krafcik said in a blog post released to the media. "This type of testing will give us the opportunity to assess the way our sensors perform in wet, cold conditions."

Waymo already has a development center in the Detroit region, in Novi, Mich., a suburb just west of the city. Last year the company announced it had struck a deal with Fiat Chrysler Automobiles for delivery of 100 hybrid Pacificas, which were added to its existing fleet of Toyota Prius, Audis (A3s and TTs), and hybrid Lexus SUVs (the RX450h).

This year Waymo announced it was adding 500 more Pacifcas to the fleet, all hybrids. That's about one shift's worth of production at Windsor Assembly, where FCA builds all its minivans, including the hybrids and Dodge Grand Caravans, on a single flex assembly line. The plant is a one-hour-drive away from the Novi development center, with an international border and a tangle of highways and driving challenges in between.

All of the test vehicles will have a human driver on board, trained to take over in an emergency.