AKIA Metrobuses Equipped with Allison Transmissions Join IETT Fleet

AKIA, which won IETT General Management’s tender bid in December 2022, completed the delivery of 72 new metrobuses equipped with Allison fully automatic transmissions.

ISTANBUL, January 2024 – The Directorate General of IETT (Istanbul Electric, Tram and Tunnel Enterprises) continues to strengthen the metrobus line (BRT) with domestic vehicles through the purchase of 72 new LF25 metrobuses equipped with the Allison Torqmatic® Series. IETT, which first purchased 60 AKIA metrobuses for its fleet in 2022, has a total 132 AKIA LF25 metrobuses with Allison fully automatic transmissions operating in total.

In Istanbul, which has a population larger than 23 European countries, 53% of public transportation is provided by wheeled transportation. A large part of this is carried out by buses and metrobuses. While more than one corporation provides this service in different metropolises of the world, IETT runs the entire bus and metrobus operation in Istanbul, enabling 1.25 million km to be covered and 4.8 million trips to be made in one day. The metrobus line, which provides transportation for 1 million passengers a day, constitutes one of the main systems in Istanbul's public transportation. With the newly delivered AKIA LF25 metrobuses, the number of metrobuses in IETT's fleet has reached approximately 700 vehicles and 20% of the total urban transportation services are carried out by metrobuses.

According to fleet data, a metrobus covers the distance of 140,000 – 150,000 km annually in Istanbul. While AKIA metrobuses delivered in 2022 reach an average of 150,000 km, they continue to perform well with routine maintenance and repair. AKIA metrobuses are used on 6 lines, which are 52 km in length with 44 stops.

AKIA LF25 metrobuses, developed by Turkish engineers and manufactured in Bursa, provide public transport solutions well suited for the heavy traffic of growing, densely populated cities. One of the highest passenger capacity public transportation vehicles in the world, AKIA metrobuses are equipped with Allison T 525R fully automatic transmissions. The AKIA 25 meter Metrobus has superior maneuverability thanks to the strong torque-producing Allison transmission paired with a Euro 6 engine and a double axle drive.

According to the information obtained from IETT officials, who stated that a total of 250,000 km distance was covered in 1 day with the Metrobus System. “In 2023, we added 92 metrobuses to our fleet, 72 of which are AKIA. The passenger capacity of AKIA metrobuses enables us to serve more passengers with fewer vehicles and decrease operational costs. We and the drivers are pleased with the vehicle performance due to the high torque. AKIA metrobuses can easily move and park in all existing lines, due to their excellent maneuverability. At this point, the fully automatic transmissions become not an option but a necessity for high capacity vehicles like metrobuses.”

The AKIA LF25 Metrobus pairs the Allison T 525R fully automatic transmission with the 12.8 liter Mercedes OM471 LA engine, with 503 horsepower (hp) and 2,500 newton-meter (N⋅m) maximum torque. The 6-gear Allison transmission has a retarder that decreases the stress level on the service brakes.

The Allison T 525R fully automatic transmission is a member of the Torqmatic Series, designed to meet the special requirements of city buses and intercity coaches with engine power up to 410 kilowatts (550 hp) and 2,600 N⋅m. The Torqmatic Series offers 6 forward speeds and 1 reverse for optimized operation and prognostic capabilities, as well as advanced electronic controls. AKIA metrobuses have Allison’s Auto Neutral At Stop and DynActive® Shifting and are equipped with FuelSense® 2.0 software which provides fuel savings. The shifting algorithm adapts the transmission control according to vehicle weight, speed and road gradient to initiate and choose the most efficient shift points for an ideal balance of fuel savings and performance.

“AKIA LF25 metrobuses are unique due to the fact that they are the first local vehicle produced in Turkey with high capacity. The AKIA LF25 metrobus has the capability of a bus with the capacity of a tram, and is equipped with innovative technology for the comfort and safety of the driver and the passengers,” said Remzi Baka, General Manager, AKIA. “The Allison fully automatic transmission is one of our indispensable components. It is extremely compatible with our vehicle. The high torque capacity, endurance, low malfunction frequency and efficient post-sales support matter for our vehicles to continuously serve without a drawback.”

Allison fully automatic transmissions are the most suitable choice for AKIA LF25 metrobuses because of their compatibility with the buses’ transfer rate. The patented Allison torque converter increases engine torque smoothly during take off and Continuous Power Technology™ provides shifting without interruptions. This offers a more comfortable ride for passengers with optimum engine and transmission efficiency, while providing a smooth power transfer to the wheels.

“Allison transmissions are preferred by many countries for BRT systems. The locally manufactured Turkish AKIA LF25 Metrobus project is very important to us,” said Atak Talas, Turkey and Middle East Regional Director, Allison Transmission. “The expectation for this kind of high performance vehicle is always immense. Allison fully automatic transmissions help vehicle manufacturers meet expectations in this regard. Being a part of the great success of Turkish OEMs domestically and in overseas markets is an honor.”

Jan 30, 2024


Allison Transmission (NYSE: ALSN) is a leading designer and manufacturer of vehicle propulsion solutions for commercial and defense vehicles, the largest global manufacturer of medium- and heavy-duty fully automatic transmissions, and a leader in electrified propulsion systems that Improve the Way the World Works. Allison products are used in a wide variety of applications, including on-highway trucks (distribution, refuse, construction, fire and emergency), buses (school, transit and coach), motorhomes, off-highway vehicles and equipment (energy, mining and construction applications) and defense vehicles (tactical wheeled and tracked). Founded in 1915, the company is headquartered in Indianapolis, Indiana, USA. With a presence in more than 150 countries, Allison has regional headquarters in the Netherlands, China and Brazil, manufacturing facilities in the USA, Hungary and India, as well as global engineering resources, including electrification engineering centers in Indianapolis, Indiana, Auburn Hills, Michigan and London in the United Kingdom. Allison also has approximately 1,600 independent distributor and dealer locations worldwide. For more information, visit allisontransmission.com.