Trabzon, Turkey’s geography presents a formidable challenge for public transportation: steep slopes that test vehicle power on every climb, narrow winding roads that demand precision maneuvering, a climate with heavy year-round rainfall that turns surfaces slick and unpredictable, and wide settlement areas that spread deep into rural regions requiring extended service routes. Every day, transit operators navigate these demanding conditions while serving approximately 70,000 passengers across 117 bus routes that have 5,200 stops. Some routes extend up to 96 kilometers in one direction with more than 250 stops, while others cover short eight-kilometer urban circuits with constant stop-and-go traffic.

The diversity of terrain—from campus routes serving Karadeniz Technical University and Trabzon University to historical and touristic destinations, from neighborhood lines to remote village connections—demands vehicles that deliver consistent performance across dramatically different operating conditions. For drivers, the workload is challenging: managing gear changes on sharp inclines, preventing rollback on wet slopes, maintaining smooth acceleration in heavy traffic and ensuring passenger comfort despite the challenging environment. This is the daily reality of keeping a mountainous Black Sea city connected and mobile.

“In our vehicle selection, our priority is the well-being and comfort of our drivers and passengers. For this reason, we choose the most advanced technologies possible. Our preference for fully automatic transmissions in our buses is also part of this policy.”
- Hakan Öztel, TULAŞ General Manager

The integrated retarder enhances control on descents and reduces brake wear, extending maintenance intervals and lowering operating costs. For drivers navigating narrow mountain roads with heavy passenger loads, the automatic transmission eliminates the workload of recurring gear changes, allowing complete focus on the road.

The impact of the transmission technology extends across multiple operational dimensions. Ersin Bal, TULAŞ Transportation Planning Manager, evaluated the contribution to efficiency and service quality: 

“Traditionally, comfort is one of the most important factors in urban public transportation. Allison fully automatic transmissions provide greater comfort for both drivers and passengers. Bus drivers benefit from the comfort of a smooth and controlled driving experience enabled by Allison’s Continuous Power Technology. Trabzon’s steep roads, year-round rainy climate, and narrow routes create important technical challenges for public transportation. With the solutions offered by Allison, it becomes possible to overcome these challenges.”

A particularly significant benefit addresses workforce development and service consistency. “The gap in driving performance that may occur between an experienced driver and a new driver is significantly reduced,” Bal explains. “This enables standardization in service.”

Fuel efficiency improvements have proven measurable and sustainable. Bal confirms that the ability to increase fuel efficiency and provide lower total operating costs was “another important reason for choosing vehicles equipped with Allison transmissions.” The combination of Continuous Power Technology, xFE fuel-saving technology and the integrated retarder reduces total operating costs while enhancing vehicle performance across all route types.

The passenger experience benefits equally from the technology. The smooth and quiet driving experience carries comfort expectations to the highest level, while drivers report that removing the need for recurring gear changes enables them to maintain greater focus on the driving experience. The proven performance of the previously delivered Otokar Doruk buses provided the confidence to expand Allison technology across the fleet.

Trends across the transit industry

TULAŞ’s technology-focused investments reflect broader trends in public transportation toward solutions that enhance accessibility, comfort and sustainability while addressing the operational realities of challenging geographies. By combining proven transmission technology with strategic fleet planning, the organization continues advancing toward its goal of providing accessible, comfortable and sustainable public transportation services across Trabzon—both in urban centers and rural areas. The success of this approach in one of Turkey’s most geographically demanding transit environments demonstrates how advanced drivetrain technology enables transit authorities to maintain high service standards across diverse operating conditions, ultimately serving communities that might otherwise face limited mobility options due to challenging terrain.