Jelly, 6 bytes

żSṀE?€

A dyadic link taking a list of numbers on each side and returning the resulting list.

Try it online! or see a test-suite*.

How?

żSṀE?€ - Link: list of numbers L, list of numbers R e.g. [1,3,3.2,2.3], [3,1,3.2,2.6]
ż - zip - interleave L & R [[1,3],[3,1],[3.2,3.2],[2.3,2.6]]
 € - for each pair:
 ? - { if:
 E - ...condition: equal 0 0 1 0
 S - ...then: sum 6.4
 Ṁ - ...else: maximum 3 3 2.6
 - } ... -> [3 ,3 ,6.4 ,2.6]

An alternative is this monadic link taking a list of the two lists, also 6 bytes:

+»=?"/

* I don't think I've ever created a test-suite footer almost three times the byte count of the code before!

Jelly, 6 bytes

żSṀE?€

A dyadic link taking a list of numbers on each side and returning the resulting list.

Try it online! or see a test-suite*.

How?

żSṀE?€ - Link: list of numbers L, list of numbers R e.g. [1,3,3.2,2.3], [3,1,3.2,2.6]
ż - zip - interleave L & R [[1,3],[3,1],[3.2,3.2],[2.3,2.6]]
 € - for each pair:
 ? - { if:
 E - ...condition: equal 0 0 1 0
 S - ...then: sum 6.4
 Ṁ - ...else: maximum 3 3 2.6
 - } ... -> [3 ,3 ,6.4 ,2.6]

An alternative is this monadic link taking a list of the two lists, also 6 bytes:

+»=?"/

* I don't think I've ever created a test-suite footer almost three times the byte count of the code before!

Jelly, 6 bytes

żSṀE?€

A dyadic link taking a list of numbers on each side and returning the resulting list.

Try it online! or see a test-suite*.

How?

żSṀE?€ - Link: list of numbers L, list of numbers R e.g. [1,3,3.2,2.3], [3,1,3.2,2.6]
ż - zip - interleave L & R [[1,3],[3,1],[3.2,3.2],[2.3,2.6]]
 € - for each pair:
 ? - { if:
 E - ...condition: equal 0 0 1 0
 S - ...then: sum 6.4
 Ṁ - ...else: maximum 3 3 2.6
 - } ... -> [3 ,3 ,6.4 ,2.6]

* I don't think I've ever created a test-suite footer almost three times the byte count of the code before!

Jelly, 6 bytes

żSṀE?€

A dyadic link taking a list of numbers on each side and returning the resulting list.

Try it online! or see a test-suite*.

How?

żSṀE?€ - Link: list of numbers L, list of numbers R e.g. [1,3,3.2,2.3], [3,1,3.2,2.6]
ż - zip - interleave L & R [[1,3],[3,1],[3.2,3.2],[2.3,2.6]]
 € - for each pair:
 ? - { if:
 E - ...condition: equal 0 0 1 0
 S - ...then: sum 6.4
 Ṁ - ...else: maximum 3 3 2.6
 - } ... -> [3 ,3 ,6.4 ,2.6]

An alternative is this monadic link taking a list of the two lists, also 6 bytes:

+»=?"/

* I don't think I've ever created a test-suite footer almost three times the byte count of the code before!

Jelly, 6 bytes

żSṀE?€

Try it online! or see a test-suite*.

* I don't think I've ever created a test-suite footer almost three times the byte count of the code before!

Jelly, 6 bytes

żSṀE?€

A dyadic link taking a list of numbers on each side and returning the resulting list.

Try it online! or see a test-suite*.

How?

żSṀE?€ - Link: list of numbers L, list of numbers R e.g. [1,3,3.2,2.3], [3,1,3.2,2.6]
ż - zip - interleave L & R [[1,3],[3,1],[3.2,3.2],[2.3,2.6]]
 € - for each pair:
 ? - { if:
 E - ...condition: equal 0 0 1 0
 S - ...then: sum 6.4
 Ṁ - ...else: maximum 3 3 2.6
 - } ... -> [3 ,3 ,6.4 ,2.6]

* I don't think I've ever created a test-suite footer almost three times the byte count of the code before!