Make the Bluestar Promise

Make the Bluestar Promise - Take the bus

Are you ready to make the bluestar promise?

We've launched a new initiative, designed to encourage people in Southampton to leave their cars at home in favour of travelling by bus.

Our city; Southampton, has been singled out by the World Health Organisation as being at its limit of unsafe air quality - and Bluestar is working with Southampton City Council to help reduce congestion.

Check out our video...

How can you take part or help make a difference?

We are asking people that live, work and shop in and around Southampton to swap just 1 car journey a week to a bluestar bus journey to make the Bluestar Promise.

It may not sound like much, but just one of our double decker buses with its Euro 6 engine - carrying upwards of 70 people - gives off far less harmful emissions than a brand new diesel car. And if thousands of people committed to this change it could have a significant impact of the air quality here in Southampton.

In recent years, Bluestar has greatly improved the frequency and reliability of bus services - most recently enhancements to our route 17 in November 2018, when the service was extended at either end to Woolston and Weston, and Adanac Park. We really do have Southampton covered.

Bluestar Promise Logo


  • I’ll travel each week with Bluestar for clean air

  • Showing our city & children I care

  • Just once each week your car stays on the drive

  • Helping clean air in Southampton to thrive

  • Help clear congestion, keep our air clean

  • Ride on the bus and make Southampton green

How many of our engines are Euro 6?

Over the last two years we have invested over 15.5 million pounds in 73 brand new low emission buses to join our fleet. It’s all about making travelling by public transport an attractive proposition in Southampton - and encouraging more people to move away from using their cars for every journey.

We are looking for local businesses to join us in our mission to make Southampton cleaner – will you join us?

Do you work for a Southampton-based business that cares about the environment, and would like to encourage their colleagues to travel to work in a more sustainable way? We are keen to work with local businesses and offer them discounted travel rates for those signing up to the Bluestar Promise.

This is a real chance for local people to help put an end to Southampton’s deteriorating air quality.  We’ve already received excellent feedback from those who plan to get involved - and expect interest in the Bluestar Promise to increase still further over the coming months.

If you or your business would like to join us, please contact us via: – with the subject 'PROMISE'

We’d love children and families to join in too.

As part of the campaign, Bluestar will be engaging with the local community. For example, we are seeking out local Brownies and Scouts groups to visit with a special ‘Promise’ bus. Any interested groups can contact the bus company via Nikki Honer - Head of Communications - and we will gladly bring our promise bus to your troop or school.

Clean Air Facts

  • A Euro 6 diesel bus emits on average 10 times less NOx per passenger/km than a Euro 6 diesel car

  • Diesel cars are the biggest contributor to roadside NOx emissions in the UK, contributing 35% of emissions compared with just 16% for buses and coaches

  • A Euro 6 standard bus emits fewer emissions overall than the average diesel Euro 6 car despite having 15 to 20 times the capacity

  • Buses are an inherently clean way to travel - a fully loaded double decker bus can take up to 75 cars off the road, reducing congestion and pollution

  • The latest generation of clean diesel British buses deliver huge environmental and economic benefits and are key to tackling the UK’s air pollution crisis

  • Congestion will bring average traffic speeds in the UK’s busiest cities down from 17mph to 12mph by 2030, resulting in higher emissions

  • Since 2015, the sector has already invested around £700 million in England outside London on over 3,000 new Euro 6 or equivalent buses

Greenhouse gas emissions

A standard 5 door car with 4 passengers in it produces twice as much CO2e / passenger km compared to a fully laden bus.

SMMT average g CO2 /km for cars produced in 2017 : 121 g CO2/km (source). Assuming 4 passengers in the car, each passenger has 30.25 g CO2 /km. The average occupancy of a car in the UK is around 1.6 people per journey, if 2 people were travelling in a car, then their associated CO2/km would be 60.5 g CO2/km.

LowCVP average g CO2e/km for double deck diesel bus at Euro VI in 2017: 1303.9 g CO2 /km. Assuming a passenger capacity of 84, a full bus would result in each km producing 15.52 go CO2/km. A bus that is running at half capacity, has a CO2 impact of 35.2 g CO2/pass km.


  • All bus technologies are clean at Euro VI.

  • Euro VI bus technologies perform as good in terms of NOx than Euro VI diesel cars – NOx target for diesel cars at Euro 6 is 0.08 g NOx/km. Average DD diesel at Euro VI is 0.33 g NOx/km. Could look to include data from DfT testing demonstrating real world performance of diesel cars is much worse than target… (DfT Vehicle Emissions Test Programme for Cars)

  • Retrofit scheme CVRAS sets NOx target of 0.5 g NOx as Euro VI equivalent level – technologies proven under lab conditions. Again lower than Euro VI diesel car

Chart showing major decrease in emissions from Euro 5 to Euro 6 diesel engines