Question about an english expression

[juliana0403]

If I say, the express bus runs every half hour.

It may mean that the bus comes 4:10, 4:40, 5:10....

Am I right?

But if the bus comes 4:30, 5:30, 6:30, how can I express it?

[Bernadetta]

the bus comes once an hour/ every hour. Maube.

[juliana0403]

thank you for your answer.

But what I was trying to say is that...

The bus comes 4:30, 5:30, 6:30...

I mean.. if i say "the bus runs every hour", it may mean 4:00, 5:00, 6:00 as

well.. I hope you understand what I am trying to say...

Do you have any other suggestion?

[rewboss]

"On the half-hour" is one possibility; or "at half past the hour"; or "thirty minutes past the hour".

[Ouisch]

I'd say it runs once an hour, on the half-hour.