General Motors' re-entry into the medium-duty truck market earned top billing as the most popular medium-duty related news item or article of 2015, and readers were also highly engaged with articles about Ford's redesigned vocational trucks and 2017 Super Duty models.

The General Motors story rolled out over two announcements in June and September. In June, GM announced it would partner with Isuzu to offer a Chevrolet-branded cabover. Then, in September, GM announced it would partner with Navistar to offer a Class 4/5 straight truck.

Let's take a closer look at the medium-duty stories that rose to the top of the list on WorkTruckOnline.com. Here's are the top 10:

1. Chevrolet Re-Enters Low-Cab Forward Market

2. GM, Navistar Collaborate on Class 4/5 Trucks

3. Ford Brings 2016 F-650/F-750 In-House

4. Navistar Details Medium-Duty Deal with GM

5. Ford Shows 2017 Super Duty Trucks in L.A.

6. Ford Unveils New Super Duty With Aluminum Body

7. Cat to Split with Navistar, Build Own Vocational Trucks

8. Peterbilt's New Vocational Model 567 Enters Production

9. EPA Sues Navistar, Says Some Engines Were Illegal

10. First 2016 Ram 3500 Rolls off Assembly Line

Thanks for making WorkTruckOnline.com your first source for medium-duty truck breaking news, analysis, and industry expertise. We look forward to providing you more great content in 2016.