Alexander Dennis Enviro500
The Alexander Dennis Enviro500 (previously known as the TransBus Enviro500) is a three-axle double-decker bus built by Alexander Dennis (formerly by TransBus) in the United Kingdom. It was unveiled in 2002 and is one of the Enviro-series bus models made by TransBus/Alexander Dennis.
The second generation Enviro500, also known as the Enviro500 MMC (MMC stands for "Major Model Change") or Enviro500 USA Standard (for buses produced in the US for the US Market), was launched in 2012, replacing the original version.
First generation (2002–2014)
The Dennis chassis for Enviro500 (also known as Trident E500) was modified from the Trident 3. It can be fitted with Cummins ISMe335 Euro III engine (later Cummins ISLe340 Euro IV/Euro V engine which uses AdBlue to reduce emission of nitrogen oxides through selective catalytic reduction process), or ISM-330 engine for the buses delivered to North America, and coupled to Voith DIWA864.3E 4-speed or ZF 5HP602 5-speed gearbox. Later Voith DIWA864.5 4-speed gearbox, ZF 6HP602 6-speed gearbox and Allison B500R 6-speed gearbox became available and gradually became the standard configurations.
Initially only the 12-metre long (39 ft 4 1⁄2 in) version of the Enviro500 was built, but in 2007 Alexander Dennis announced the production of the 12.8-metre long (41 ft 11 7⁄8 in) version, and an 11.3-metre-long variant followed in 2008.
The vehicle exceeded some design limitations in Hong Kong, the first city where the model was used, prompting the local Transport Department to make some exclusions in order to make the buses available to KMB on time.
- The width of the bus is 2.55 metres (8 ft 4 3⁄8 in) exceeding the limit of 2.5 metres (8 ft 2 3⁄8 in). The width of 2.55 metres (8 ft 4 3⁄8 in) was approved by the European Union, becoming the current standard.
- A fixed glass replaced the emergency door at the rear of the upper deck, but with more hammers available for emergency.
- The front indicators are the smallest of all current models of Kowloon Motor Bus.
The facelifted version of Enviro500 body, first built in late 2003, have revised frontal and rear designs. This version of Enviro500 bodywork was also available with Volvo B9TL chassis.
Kowloon Motor Bus
The Enviro500 is the first model of second-generation low-floor buses for Kowloon Motor Bus, with straight staircase and plug door (only at the exit) fitted. All KMB's Enviro500 buses had a bronze band added to the champagne livery to differentiate them from the first-generation low-floor buses.
When TransBus announced the development of the Enviro500, KMB became the launch customer by changing the last 20 of an order for 100 Dennis Trident 3s to the Enviro500 in 2002. Later in the same year, KMB placed an order for a further 100. The first Enviro500 arrived in Hong Kong on 12 November 2002 and was registered in January 2003 with all in service by November 2003.
In 2003 KMB placed another order for 65 Enviro500s, quickly followed by a further 50. The bodywork of these buses received a number of minor modifications. The first 112 buses entered service between November 2003 and June 2005, and the remaining three buses were registered by its subsidiary Long Win Bus.
Due to the commencement of the KCR West Rail in late 2003 and KCR Ma On Shan Rail in late 2004, the Transport Department requested KMB to reduce its fleet size, so the registration of these four batches of KMB Enviro500 were delayed and some of them were stored before entering service.
In 2005, KMB ordered a further 25 with modified bodywork and new Alexander Dennis badge, 24 of them (five had their electronic route destination displays supplied by Gorba instead of Hanover) entered service in early 2006. The last one, a Euro IV-engined prototype, with fleet number ATEU1 (originally ATE257), entered service on 24 May 2006. In 2009, it reemerged as a Euro V-engined bus.
In late 2005, KMB ordered 15 more buses which entered service in August 2006.
Later a batch of 9 buses with Euro IV engines was ordered for delivery in 2009, which entered service in mid-2009. One of them was fitted with luggage rack after body assembly. It was quickly followed by another batch of 46 buses for delivery in 2010, 20 of them were eventually diverted to Long Win Bus, and 26 buses entered service with KMB in 2010-2011.
A batch of 35 buses with Euro V engines was ordered for delivery in 2010/11, 30 of them were eventually diverted to Long Win Bus, and 5 buses entered service with KMB in 2011.
In July 2008, one was written off (ATE180) after being burnt out in KMB's depot in Tin Shui Wai on 31 March 2008.
Long Win Bus
Long Win Bus registered three Enviro500 buses, which were originally ordered by Kowloon Motor Bus, in August 2005 to cope with the increased demand for bus services after the opening of Hong Kong Disneyland.
In late 2005, Long Win Bus ordered five more which had luggage racks fitted when new, entering service in June/July 2006.
A further batch of seven buses with Euro IV engines had been ordered for delivery in 2009. The first six buses entered service in mid-late 2009. The last one, which was fitted with coach seats, entered service in October 2009. These were followed by further five buses, with the first four being registered in December 2009; the last one, which was fitted with coach seats, entered service in April 2010. In 2010, Long Win Bus received 20 more Enviro500 buses with Euro IV engines.
A batch of 6 Enviro500 buses with Euro V engines was ordered for delivery in 2010/11. These, together with 30 diverted from KMB's order, were put into service between 2011 and 2013.
Until 2014, Citybus has 220 Enviro500s in services, they are all 12 metres long.
Citybus ordered 10 Enviro500s with Euro IV engine and luggage racks, soon after its sister company New World First Bus's order. The first batch of chassis arrived Hong Kong in the third quarter of 2007 for body assembly in NWFB depot at Chong Fu Road. They entered service in December 2007/January 2008.
A further batch of 18 buses with Euro IV engines had been ordered for delivery in 2009, they entered service in 2009. They were followed by another 77 buses with Euro V engines, they entered service in 2010/11. In 2011 Citybus ordered 115 Enviro500s, with three fitted with luggage racks.
Kowloon-Canton Railway Corporation originally ordered 9 12-metre long (39 ft 4 1⁄2 in) Euro IV-engined Enviro500 buses in early 2007 for its Feeder Bus service. The first completed bus arrived Hong Kong on 24 November 2007, then registered in February 2008 and entered service in March 2008; the rest of them entered service in March/April 2008.
Later a batch of 15 buses with Euro IV engines was ordered for delivery in 2009, they were first registered in April–August 2009. This was followed by another order for 9 buses in 11.3-metre (37 ft 7⁄8 in) length which entered service in 2012.
New World First Bus
New World First Bus ordered 18 Enviro500 buses with Euro IV engine in early 2007. 17 buses entered service in early/mid-2008, another one (fleet number 5504) was shipped to Australia in March 2008, after body assembly, for demonstration in several cities between April and May 2008, it finally entered service in June 2008.
In 2008 New World First Bus ordered 20 11.3-metre long (37 ft 7⁄8 in) examples with Euro IV engines for delivery in 2009. They entered service in July–October 2009. A further batch of 20 similar buses with Euro V engines entered service in early 2010.
In 2010, a batch of 24 12-metre long (39 ft 4 1⁄2 in) buses with Euro V engines was ordered for delivery in 2010-2011. They entered service in January–May 2011.
In 2011 New World First Bus ordered 13 12 m-long Enviro500s, all of them entered service in May 2012. These were followed by another 28 12 m-long buses which started to enter service in 2013.
In 2020, 5 Enviro500s (5550-5554) were planned to be converted into open-top buses for tourist routes H1, H1A and H2. as of June 2020, only 5550 has finished the conversion process.
Currently there are 123 Enviro500 buses in service with New World First Bus.
CLP Group ordered five Enviro500 buses with Euro IV engines for its staff shuttle bus service in 2008. The specification is similar with Citybus's Enviro500, but without wheelchair place and standees. They entered service in June 2009.
In August 2008, First Glasgow ordered a batch of 25. They entered service between April and June 2009.
In 2004, Alexander Dennis started to explore the North American market for its Enviro500. The American version of Enviro500 have modified bodies and redesigned fuel tanks, which enable the straight staircase to be moved forward. Alexander Dennis built four left hand drive Enviro500 (one 12-metre long or 39-foot-4 1⁄2-inch bus and three 12.8-metre long or 41-foot-11 7⁄8-inch buses) for demonstration in the United States and Canada.
Bus operators which evaluated the Enviro500 included Community Transit of Snohomish County, Washington (December 2005), Unitrans of Davis (January 2006, two weeks), OC Transpo of Ottawa (28 June to 12 July 2006 and February 2007), San Francisco Municipal Railway of San Francisco (November 2007 to January 2008) and the Réseau de transport de la Capitale of Quebec City (March 2013).
Dennis also built one 12-metre Enviro500 demonstrator for long-term loan. It was first loaned to Community Transit between 2007 and 2009 which put it into service on 1 August 2007, the bus was used on commuter routes between Seattle and various points in Snohomish County during its first year in operation. From September 2010, it was loaned to Strathcona County Transit on a one-year lease for the operator's one-year-long double-decker pilot project. The pilot is part of an exploration of different high-capacity bus types to carry more passengers on the high-demand commuter routes, which are between Strathcona County and Edmonton; an articulated bus is also being evaluated as an alternative and there is no commitment to put any Alexander Dennis model or any double-decker design into permanent service. This bus becomes the first double-decker to be used for regular transit service in Alberta.
In 2011, Alexander Dennis unveiled a restyled Enviro500 body design for the North American market, which had the same front as the Enviro400. This was first used on the "Go-Anywhere" version developed for GO Transit, which has an overall height of 4.115 m (13 ft 6 in). This height would become standard with the MMC model introduced in 2015.
BC Transit, the first Canadian operator of double-decker transit buses, ordered nine Enviro500s, which were allocated to the Victoria Regional Transit System in Victoria, British Columbia with fleet numbers 9041-9049. These vehicles entered service in early 2005, joining the nineteen Trident 3 buses already in service since 2000. These were followed by another 26 (9501-9526) which entered service in 2008; sixteen of them (9501-9516) were originally allocated to Victoria and the other ten (9517-9526) to the Kelowna Regional Transit System in Kelowna. All units are currently allocated to Victoria.
In 2009, BC Transit received one hybrid-electric Enviro500H (now numbered 9527) for evaluation, and followed it up in 2011 by purchasing one Enviro500 demonstration vehicle built in 2007 but repowered with an EPA 2010-compliant Cummins ISL engine (now numbered 9528). Three more Enviro500s (9529-9531) entered service in 2013, built in 2008 and acquired second-hand from OC Transpo (see below). All of these vehicles are used in Victoria.
GO Transit, the regional transportation authority serving the Greater Toronto Area in Ontario, currently operates 127 12.8-metre-long Enviro500s in its fleet. Like its fleet of coach buses, they have only one door in the front. Earlier, it tested a double-decker Trident 3 on loan from Victoria in May 2002, which had an extra rear door. However, it did not place any orders until early 2008, when it introduced twelve commuter-type Enviro500s (numbered 8000-8011), Ten extra units (8012-8021) entered service in early 2009. Both of these batches have a height of 4.2 metres (13 ft 9 3⁄8 in), making them too high to meet bridge clearance (under overpasses etc.) requirements in the province.
After the introduction of the Go-Anywhere version of the Enviro500, In 2012, GO Transit ordered 25 of these new models (8101-8125), also 12.8 metres (41 ft 11 7⁄8 in) long. The first bus was delivered on 3 April 2013 and the remaining 24 in May 2013. These were followed by seventy in 2014, delivered in two batches (8126-8165 and 8166-8195), and a further ten (8196-8205) in 2015.
OC Transpo of Ottawa, Ontario, purchased three transit-type Enviro500s in 2008 as part of a one-year pilot project to investigate the use of double-deckers on high-capacity routes. Numbered from 1201 to 1203, they were operated on a variety of routes, but their height, which exceeded the requirements of the MTO, made them impractical for continued use. These three demo buses were sold to BC Transit in the summer of 2012 (see above).
OC Transpo subsequently ordered 75 Go-Anywhere Enviro500s (numbered 8001-8075) for delivery in 2012/13, the first one officially arriving on 23 August 2012. 73 of 75 these buses are in service as of 12 January 2019.
Strathcona County Transit
Strathcona County Transit ordered 14 transit-type Enviro500s (numbered 8001-8014) for their commuter service between Sherwood Park and Edmonton, Alberta, with the first arriving in late 2013 and subsequent buses arriving by the spring of 2014. They chose double-deckers over articulated transit and motor coaches after a year of testing between September 2010 and October 2011.
Gray Line New York, owned by Coach USA ordered 20 open-top Enviro500 for its sightseeing operations in New York and put them into service in spring 2005, these were the first open-top Enviro500 built (another 13 would later be ordered). Gray Line also received three single-door Enviro500 in summer 2005 for operation in San Francisco.
Citizens Area Transit (now RTC Transit) of Las Vegas had its first 50 Enviro500s enter service by October 2005. The service, marketed as "The Deuce", runs along the Las Vegas Strip. Certain high-traffic routes, such as along Maryland Parkway and Nellis Boulevard, have also used these buses. They offer extra ventilation grilles outside the engine compartment to cope with Southern Nevada's dry desert climate and high summertime temperatures. Las Vegas's Enviro500s have the largest air conditioning system ever created for a transit vehicle, with eight fans fitted on the air conditioning unit. As of October 2006, CAT had firm orders for another 41 of the type worth $29.8 million; these were delivered in late 2007. A further 40 had also been ordered for delivery in 2008; these were 12.8 meters (41 ft 11 7⁄8 in) long and had a second staircase to speed loading and unloading. All these vehicles were used for regular fixed-route operations, not for sightseeing operations.
Les Cars Rouges, a sightseeing company, ordered 16 open-top Enviro500 for sightseeing operations in the US, delivery of these buses started in early 2007. Eight of the Enviro500 are destined for San Francisco, and the rest of them are destined for Washington, D.C.
Community Transit signed a five-year contract on 2 July 2009 with Alexander Dennis to deliver up to 120 Enviro500 coaches after the trial of an Enviro500 demonstrator. The company introduced a fleet of 23 12.8 m (41 ft 11 7⁄8 in) Enviro500s in 2011.
Unitrans (the student-run transit service of University of California, Davis, known for years for its operation of former London Transport double-decker buses) ordered two Enviro500 which were delivered in early 2010; these are the first batch of Enviro500s with the bodywork assembled by ElDorado National.
SLO Transit ordered one Enviro500 which entered service in late 2010.
Hele-On Bus introduced one 12.8m Enviro500 in the first half of 2011.
A Enviro500 with Kiwi Bus Builders bodywork was unveiled in 2011. This bus was the first Enviro500 with bodywork constructed by other bodybuilders, it was built for Rockleigh Tours in Melbourne. After a five-year quest to acquire a new double-decker with disabled access, the only company willing to supply a chassis was ADL, though it needed to be modified to make it narrower to meet Australian standards. Kiwi Bus Builders narrowed the chassis and built the body to Rockleigh Tours requirements.
Republic of Korea (demonstration only)
Enviro500 bodywork on Volvo B9TL chassis
Kowloon Motor Bus received one prototype Enviro500-bodied Volvo B9TL in 2005, a further 85 buses were put into service between 2006 and 2008.
Long Win Bus received ten buses between 2007 and 2008, one of them was built as an airport coach.
Dublin Bus is the only operator to receive Enviro500-bodied buses without air conditioning. The first batch of twenty entered service in 2005 in Donnybrook garage. Another batch of fifty, with slightly longer front overhang and Euro IV engine, entered service in 2007 in Phibsboro depot.
The first twenty buses of the 2005 batch were withdrawn and sold in December 2018.
Second generation (2012–present)
In 2012, Alexander Dennis unveiled a new generation Enviro500 (also known as the Enviro500 MMC) with a new chassis design. The chassis (also known as the Trident E500 Turbo and E50D/E50H) had the longitudinally-mounted engine and gearbox slightly offset to the left. The Cummins ISLe engine was retained, with choices of ZF EcoLife and Voith DIWA gearbox. Like the Enviro400 with straight staircase, the shape of fuel tank was specifically adopted to be mounted under the staircase. All the axles utilised were supplied by ZF instead of Dana.
The bodywork was also redesigned, with a more angular front-end design based on the Hong Kong version of the Enviro400. It has a new design of staircase known by Alexander Dennis as the "Square-Case", whose size was similar to that of the spiral staircase but with all steps being rectangular shaped.
A hybrid-electric version of this bus model with a Cummins ISBe engine and the BAE Systems HybriDrive series hybrid system had been built in small numbers.
Later in 2014, Alexander Dennis unveiled this second generation Enviro500 in North America, with a new design of bodywork similar with the Enviro400 MMC launched earlier that year, featuring rounded top edges and a vertically oriented headlamp cluster. This bodywork design was also adopted by the Enviro500s built for Hong Kong since 2015.
Two versions of the Enviro500 have been developed for the North American market: the standard 4.1 m (13 ft) height model with a length of 12.9 m (42 ft 3 7⁄8 in), and a new, lower-height 3.9 m (13 ft) Super-Lo variant with a longer length of 13.8 m (45 ft 3 1⁄4 in), designed for high-capacity, interurban transport.
Citybus ordered one new generation Enviro500 in 2011 - 8320 (in conjunction with the 115 older Enviro500), soon followed by further order of 155. 107 of these were for the 12-metre-long version, including 66 fitted with airport coach specifications (8000-8065) while the rest were standard passenger buses (8321-8360). The other 49 were 11.3-metres-long (9100-9148). The first 4 airport coaches entered service in March 2013 and in 2014. Citybus ordered a further 104 new generation Enviro500s which were all the 12-metre long (39 ft 4 1⁄2 in) version and possess a high seating capacity for 90 passengers, 8361 to 8399 and 8402 to 8466.
In mid 2014, Citybus received a 12.8-metre long (41 ft 11 7⁄8 in) Enviro500 demonstrator, 6300, and became the second operator in Hong Kong after KMB to receive such a model. Later that year, the operator received 2 hybrid versions of the Enviro500, 8400 and 8401, becoming the third operator of such a type in Hong Kong. Citybus then went on to order a further 70 new generation 12-metre-long Enviro500s of which the first was delivered in January 2015, 8467 to 8536, increasing the total of 12-metre Enviro500 to 216 in Citybus.
From late 2015 to 2018, Citybus received further 263 12.8-metre-long Enviro500(6301-6443, 6501-6583, 6800-6836), but with restyled front and rear. 6800-6836 were fitted with luggage racks in the lower saloon.
Among the Citybus Enviro500 fleet 8361-8390 were sold to NWFB in 2017, repainted in NWFB's white-and-orange livery and re-numbered 5720-5749.
A further announcement in 2020 stated that 12 buses (8525-8536) were to be transferred to NWFB as well, with 3 already being put into service on NWFB routes as of June 2020.
From May 2018, Citybus received further 10 12-metre-long Enviro500s (8537-8546) and 38 12.8-metre-long Enviro500 (6444-6459, 6584-6588, 6837-6843) with Euro VI engine.
Between 2019-2020, more 12.8-metre-long Enviro500s were transported to Hong Kong and put into service. Their fleet numbers are 6460-6497. 2 (6493, 6495) were painted with vintage livery to celebrate the 40th anniversary of Citybus. Another 28 coaches (6844-6871) were put into service between 2019 and 2020.
In 2020, Citybus placed a further order of 10 11.3-metre-long Enviro500s (9149-9158) with Euro VI engine. 2 of them have already been transported to Hong Kong and are painted with vintage livery to resemble Citybus' Leyland Olympians.
In 2019, 6448 was retired prematurely due to arson attack when it was parking in Tuen Mun.
Kowloon Motor Bus
Placement of subsequent orders increased the total to over 2100, including 1652 12-metre Euro V version (ATENU), 222 12.8-metre Euro V version (3ATENU), two 12-metre Euro VI version (E6T), 194 12.8-metre Euro VI version (E6X), and 101 11.3-metre Euro VI version (E6M).
2 ATENUs had retired prematurely due to fire. On 4 May 2018, ATENU274 (SP9007) caught on fire while travelling on Tate's Cairn Highway as route 277X. And on 11 May 2019, ATENU53 (SD6028) caught on fire while travelling on Connaught Road Central as route 961. Both received damage beyond repair.
A third ATENU also caught on fire. On January 5th, 2020, ATENU129 (SH963) caught on fire while it was parked in Yuen Long Depot. However, it was unconfirmed that if the bus was retired.
Long Win Bus
Long Win Bus ordered 22 new generation Enviro500 in 2012, with a further 19 buses diverted from KMB order and follow by another 6 buses. In 2014, LWB placed a further order of 26 new generation Enviro500 with airport coach specification. A further batch of 91 was ordered in 2015 including 40 12-metre buses and 51 12.8-metre and another batch of 62 more was ordered in 2016 with 50 12-metre buses and 12 12.8-metre.
MTR Bus ordered 6 11.3-metre-long new generation Enviro500 in 2012, which were delivered and entered service in 2013. Before the 6 new generation Enviro500 were registered, MTR ordered more 28 11.3-metre-long new generation Enviro500 which were delivered and entered service in 2014 and 2015. Then 8 more delivered and entered service in 2017 and 2018.
On May 5th, 2020 bus 543 caught on fire while travelling on Tuen Mun Road. It was believed the bus will receive an early retirement due to critical damages.
New World First Bus
New World First Bus ordered 12 new generation Enviro500 in 2013, they are all 11.3-metre-long version. The buses (4040 - 4051) were in service between 2013 and 2014.
In 2014, NWFB ordered another 87 Enviro500 (5583 - 5669), all of them were 12-metre-long version and included one Enviro500 with hybrid version (fleet no. 5600), becoming the second operator receiving hybrid version.
In 2016, NWFB received further 50 more 12-metre-long Enviro500 (5670 - 5719) followed by 76 more 12.8-metre-long Enviro500 (6100 - 6175) and another 40 more 11.3-metre-long version (4052 - 4091) in 2017, but with restyled front and rear.
In 2017, NWFB received 30 second-hand 12-metre-long Enviro500s from Citybus, with new fleet numbers from 5720 to 5749 (originally 8361 to 8390). It also received 22 12.8-metre-long Enviro500 (6176 - 6197) between 2017 and 2018.
In 2018, NWFB received further 90 12-metre-long Enviro500s (5750-5839) and 12 12.8-metre-long Enviro500(6198-6209) with Euro VI engine.
A further 12 (Fleet numbers 5840-5851) were expected to be transferred from Citybus (Original Fleet Numbers 8525-8536) in 2020, with 3 already put into service on NWFB routes as of June 2020.
CLP Group ordered one Enviro500 to replace one old version Enviro500 written off after an accident. It was delivered in late 2015.
SMRT Buses initially ordered 103 Enviro500 double deckers for delivery in 2014 but the order was expanded to 201 in total, with an additional 98 buses to be used for Land Transport Authority (LTA)'s Bus Service Enhancement Programme (BSEP). As of Sunday 13 July 2014, the first double deckers started service on route 972.
Bus Contracting Model (BCM)
On 25 April 2019, the Land Transport Authority announced  that they had awarded the tender to Alexander Dennis (Singapore) Services Pte. Ltd to procure 50 units of three-door Enviro500s after successful trials of the 3 door concept bus.
Prasarana Malaysia had ordered 40 units of Euro III engined Enviro500 buses for Rapid KL services and is being operated by Rapid Bus, one of subsidiaries of Prasarana Malaysia. The buses are serving the high capacity routes around the Klang Valley, especially from Cheras and Shah Alam to the capital city of Kuala Lumpur as well as the inner routes in the city centre.
Lately, Prasarana Malaysia ordered another 3 units of Enviro500 buses for Rapid Penang.
New Zealand operators began purchasing Enviro 500s in 2015, the following operators have purchased the type:
- Howick & Eastern: 19
- NZ Bus: Auckland - 23 (2016) x 54 (2018) Wellington x 17 (2018, delayed entry into service until 2019)
- Birkenhead Transport: 8
- Ritchies Transport Holdings x 23 (1356-1374 AT NEX livery. 1375-1377 AT Metro livery).
- Mana Coach Services (Under Newlands branding) x 6 (2018)
Enviro500 MMCs produced in the United States are made under the title of 'USA Standard' instead of MMC. Production of these models has taken place since September 2014 in a newly-opened facility originally owned by Ameritrans Bus, Inc. in Nappanee, Indiana. By December 2016, Alexander Dennis took over all manufacturing operations within the facility and added a second body assembly line to increase production.
As for operators, Community Transit in Snohomish County, Washington currently has a fleet of 62 Enviro500 coaches, including 39 Enviro500 'USA Standard' coaches. After its initial order of 23 Enviro500 coaches proved to be well suited for the agencies commuter routes with direct peak-hour service to Downtown Seattle, the agency placed orders for 17 more Enviro500 'USA Standard' coaches in 2013, 5 more in 2014, and 17 more in 2016.
At the same time as Community Transit placed its order, neighboring agency Sound Transit, the regional operator in Seattle, also ordered five Enviro500 'USA Standard' coaches. The agency used the coaches to test their suitability for use Sound Transit Express routes. After proving to be successful, Sound Transit placed an order for an additional 32 Enviro500 'USA Standard' coaches in 2016 which would replace 32 articulated buses loaned from Sound Transit to Community Transit.
After a successful pilot in 2015, AC Transit awarded a contract to Alexander Dennis for 10 double-deck buses in 2016; the contract includes options for an additional 19 buses, divided as 10 buses for AC Transit, 3 buses for Unitrans, and 6 buses for WestCAT. Transbay service using Enviro500s began in December 2018.
In 2015, GO Transit, Canada's largest operator of double-deckers with over 120 vehicles in its fleet, became the launch customer for the Super-Lo variant of the "SuperLo" Enviro500s. Their lower height of 3.9 metres allows them to fit into terminals with height restrictions, particularly York Mills and Yorkdale Terminals. The first batch of 38 vehicles (8300-8337) was delivered in 2016. The chassis for these vehicles are being manufactured at a purpose-built factory in Vaughan, north of Toronto, creating up to 30 new full-time jobs. As a suburban bus operator, the Enviro500 has single doors at the front.
Strathcona County Transit received five Enviro500s in 2016. An additional five were ordered in 2017/2018 and entered service in 2019. Two more entered service in early 2020.
OC Transpo ordered 43 new Enviro500 "Go Anywhere" models for delivery starting in late 2015 with the last entering service September 2016. These new buses will also be fitted with Wi-Fi, of which 15 currently have Wi-Fi as a test project. A further 17 buses entered service in 2017, making the current active fleet of over 130 units, with plans for other units pending. OC Transpo's Enviro500 have doors at the front and the middle. 8155 was damaged in a serious collision with a Westboro transit station shelter.
In September 2015, Alexander Dennis announced the order of 19 Enviro500s with twin staircases and three doors for PostAuto, Switzerland, delivery started in 2017.
Metrobús of Mexico City ordered 90 Enviro500 after evaluating one original version Enviro500 demonstrator in late 2014. They are scheduled for delivery in 2016. The delivery has been delayed and as of 2017 only 22 out of 90 buses have arrived to Mexico City. The service of Metrobus is expected to start in October 2017 with the route that starts from Indios Verdes to Campo Marte.
In October 2015 Berliner Verkehrsbetriebe (BVG), the public transport operator of Germany's capital, commenced a six-week trial of an Alexander Dennis Enviro500, as part of a bigger testing programme for a new series of buses for the city. In October 2018, the BVG ordered 200 Enviro500 in order to replace the MAN Lion's City DD.
- Length: 11.3 m (37 ft 7⁄8 in), 12.0 m (39 ft 4 1⁄2 in), 12.5 m (41 ft 1⁄8 in), 12.8 m (41 ft 11 7⁄8 in)
- Width: 2.50 m (8 ft 2 3⁄8 in), 2.545 m (8 ft 4 1⁄4 in) 2.55 m (8 ft 4 3⁄8 in)
- Height: 3.9 m (12 ft 9 1⁄2 in), 4.1 m (13 ft 5 3⁄8 in), 4.2 m (13 ft 9 3⁄8 in), 4.4 m (14 ft 5 1⁄4 in)
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