It appears that you could go up to the truck driver and buy a bottle of Whistle directly from him if the sign below the truck cab is to be believed. Try that today with a Coke or Pepsi truck driver (or better yet, a Budweiser truck driver).

The truck is a Traffic Truck built by the Traffic Motor Truck Company of St. Louis, Missouti. A more detailed description of these trucks is shown here on Shorpy: https://www.shorpy.com/node/4014

One detail of the truck that is shown more clearly here is the opening cab windshield which may get in the way of the driver's view of the road. From this picture it appears the windshield is actually far enough forward that it would not get close enough to hit him in the face when the truck goes over a large bump in the road.

This truck, and the people, do not appear to be shown in the other picture (this truck has much more signage on the side of the body).

Note the "Traffic" logo on the side of the chassis above the drive shaft. A close up this logo is shown below.

In this side view of the truck you can still see a portion of the triangular piece on the side of the hood that also helps correctly identify these vehicles.

I love before and after pairs like this -- great work.

Well not the truck, but rather the location of the photo. It seemed sensible that the site might be in the vicinity of the former Whistle Bottling Works. I finally trotted down to the location today, and sure enough, the photo of the truck was taken directly in front of the bottling plant looking across the street (400 block F street N.E.)

It was bottled until (at least) in the 70s in Columbus, OH by a plant located on W. Fifth Avenue near Grandview. Today, that plant is a moped shop.

They used to have around 20 flavors of Whistle, and in the early 70s they opened some satellite stores in some of the small strip malls and you could mix up a case of whatever flavors you wanted.

Thirsty? Just Whistle!

Introduced no doubt after the "Beverage Wrapped in Waxed Paper" failed in test markets.

Wonderful detail (as with nearly every photo). Did the fellow on the right forget his shirt collar or maybe he is just not used to wearing a tie and did not know where it went.

Wonderful photo, particularly like the blur around the leaves on the tree on the right, I guess a long exposure.

Apparently you can still buy this orange soda. It appears to have been available in other flavors as well, and first appeared in 1916.

This is a great photo. I love the driver and his polished boots. The boy looks like he poured his Whistle on the ground.