USA Apocalyptic film 70s UNSOLVED for 16 years

I been trying to track this scene down for 16 years, or longer. Probably a 1970s film. It is a USA film.

It was so long ago I cannot remember if there are zombies in the film.
It is NOT post-apocalyptic, i.e. we only see what happened in the days after whatever has happened. There are no "wastelands" or "New World Order" etc.

At the end of the film the protagonists (I think, a young couple male/female) meet a black man in a clothes store. He takes them in a car or a school bus to his community. We look down on the car/bus as it drives up a road on a hillside in what must be Los Angeles. The car/bus arrives at a road-block. The road is blocked by cars or a school bus. The "gate" is opened by moving the vehicles aside. They drive in and park. The "gate" is closed again. The road is about 3 car widths wide, and has a concrete surface. It has hair-pin bends in it. The road-block is on one such hair-pin-bend.

They stop the vehicle a few metres from a pitched roof building, which itself is only about 50m from the road-block. They get out a nd walk towards the building. The new arrivals walk in through the back door of the house, are welcomed into a friendly environment-there is no dialogue. They are safe. THE END. credits start to roll.

, The shot pans around 180° to show that this house is high up on a hillside overlooking the city sky-line, with its tall buildings in the distance and the Sun setting behind them. And I would think it is Los Angeles.

The whole scene I just described, "The scene shot from a helicopter", from arriving in the car at the gate, the gate being opened, to the sunset in the end credits is about 3 minutes runtime.

In an earlier scene, I'm pretty sure the black male is wearing or trying on a tan leather jacket in a store and it is this guy who takes them to safety.

Also I am sure that this whole thing started out because the survivors were trapped in a road tunnel in a car overnight. And on this night people who were not in the tunnel saw lights in the night sky or something. And when our survivors emerged from the tunnel in the morning, they found that everyone outside had turned into red dust.

I believe there is also a radio station which is on automatic and trying on clothes in a store.

Do not be in any doubt, the film I am looking for is an apocalyptic one that ends with the "helicopter shot" as described. Adding the extra information always throws confusion into the thread because the scenes are similar to other films. I am certain it is just a single film the extra information is just to aid in the search, but whether it is my memory joining two films together is immaterial because I am looking for a USA apocalyptic film 70s/80s that ends as described.

It is not:
(By the way I had never seen any of these until I watched them to eliminate them from my search. And the scenes in these films do not match those in my memory.)
Night of the Comet (1984)
Where Have All the People Gone (1974)
The Omega Man (1971)
The Quiet Earth (1985)

A list on IMDb here http://www.imdb.com/list/ls000833832

I found a good list on wiki. Maybe it's in here. Maybe you can eliminate some of these for me?
**Remember** We are only looking for the ending as described above.

https://en.wikipedia.org/wiki/List_of_apocalyptic_films

RED * = Not my film.

Pre 50s Marked red due to being B&W

* Deluge (1933)
* Verdens Undergang (1916)
* La fin du monde (1931)
* Things to Come (1936)


50s Unlikely to be in colour? B&W marked red

* The Day the Earth Stood Still (1951)
* Day the World Ended (1955)
* Five (1951)
* Invasion of the Body Snatchers (1956)
* Kiss Me Deadly (1955)
* The Lost Missile (1958)
* On the Beach (1959)
* Robot Monster (1953)
* The War of the Worlds (1953)
* When Worlds Collide (1951)
* The World, the Flesh and the Devil (1959)
* World Without End (1956)


60s

* Il pianeta degli uomini spenti (1961)
* The Bed Sitting Room (1969)
* Beyond the Time Barrier (1960)
* Crack in the World (1965)
* The Creation of the Humanoids (1962)
* Daleks' Invasion Earth 2150 A.D. (1966)
* The Day the Earth Caught Fire (1961)
* The Day of the Triffids (1962)
* Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964)
* Fail-Safe (1964)
* Il seme dell'uomo (1969)
* In the Year 2889 (1967)
* La jetée (1962)
* The Last Man on Earth (1964)
* Sekai daisensô (1961)
* Last Woman on Earth (1960)
* Night of the Living Dead (1968)
* Panic in Year Zero! (1962)
* Planet of the Apes (1968)
* This Is Not a Test (1962)
* The Time Machine (1960)
* The Time Travelers (1964)
* The War Game (1965)


70s
* The Andromeda Strain (1971)
* Battle for the Planet of the Apes (1973)
* Beneath the Planet of the Apes (1970)
* Beware! The Blob (1972)
* Black Moon (1975)
* A Boy and His Dog (1975)
* Colossus: The Forbin Project (1970)
* Conquest of the Planet of the Apes (1972)
* Damnation Alley (1977)
* Dawn of the Dead (1978)
* A Distant Thunder (1978)
* End of the World (1977)
* Escape from the Planet of the Apes (1971)
* The Final Programme (1973)
* Gas! -Or- It Became Necessary to Destroy the World in Order to Save It. (1970)
* Holocaust 2000 (1977)

* Invasion of the Body Snatchers (1978)
* The Last Wave (1977)
* The Late Great Planet Earth (1979)
* The Living Dead at Manchester Morgue Non si deve profanare il sonno dei morti (1974)
* Logan's Run (1976)
* Mad Max (1979)
* No Blade of Grass (1970)
* The Noah (1975)
* The Omega Man (1971)
* Phase IV (1974)
* Quintet (1979)
* Ravagers (1979)
* The Shape of Things to Come (1979)
* Silent Running (1972)
* Soylent Green (1973)
* A Thief in the Night (1972)
* The Ultimate Warrior (1975)
* Where Have All the People Gone (1974)
* Wizards (1977)
* Zardoz (1974)

80s
* Antropophagus (1980)
* The Apple (1980)
* Das Arche Noah Prinzip (1984)
* Warlords of the 21st Century (1982)
* The Blood of Heroes (1989)
* Bunker Palace Hôtel (1989)
* Cherry 2000 (1987)
* Cyborg (1989)
* The Day After (1983)
* Def-Con 4 (1985)
* Le dernier combat (1983)
* Escape from New York (1981)
* Il giustiziere della strada (1983)
* Flash Gordon (1980)
* Image of the Beast (1980)
* Land of Doom (1986)
* Mad Max 2 (1981)
* Mad Max Beyond Thunderdome (1985)
* Malevil (1981)
* The Martian Chronicles (1980)
* Millennium (1989)
* Miracle Mile (1988)
* Kaze no tani no Naushika (1984)
* Nightmare city (1980) Incubo sulla città contaminata (1980)
* Night of the Comet (1984)
* The Prodigal Planet (1983)
* The Quiet Earth (1985)
* The Seventh Sign (1988)
* Steel Dawn (1987)
* The Terminator (1984)
* Testament (1983)
* The Thing (1982)
* Threads (1984)
* Fukkatsu no hi (1980)
* When the Wind Blows (1986)
* World War III (1982)